diff --git a/CMakeLists.txt b/CMakeLists.txt
index 9e3bb336..275a1d03 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -7,12 +7,6 @@ set_property(GLOBAL PROPERTY USE_FOLDERS ON)
 set(CMAKE_CONFIGURATION_TYPES "Debug;Release")
 enable_testing()
 
-function(set_static_flags)
-  if (NOT APPLE)
-    set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -static-libgcc -static-libstdc++")
-  endif()
-endfunction(set_static_flags)
-
 include_directories(src contrib/epee/include external "${CMAKE_BINARY_DIR}/version")
 if(APPLE)
   include_directories(SYSTEM /usr/include/malloc)
@@ -76,8 +70,8 @@ else()
   set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} ${DEBUG_FLAGS}")
   set(CMAKE_C_FLAGS_RELEASE "${CMAKE_C_FLAGS_RELEASE} ${RELEASE_FLAGS}")
   set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} ${RELEASE_FLAGS}")
-  if(STATIC)
-    set_static_flags()
+  if(STATIC AND NOT APPLE)
+    set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -static-libgcc -static-libstdc++")
   endif()
 endif()
 
@@ -85,7 +79,7 @@ if(STATIC)
   set(Boost_USE_STATIC_LIBS ON)
   set(Boost_USE_STATIC_RUNTIME ON)
 endif()
-find_package(Boost 1.53 REQUIRED COMPONENTS system filesystem thread date_time chrono regex serialization atomic program_options)
+find_package(Boost 1.53 REQUIRED COMPONENTS system filesystem thread date_time chrono regex serialization program_options)
 if((${Boost_MAJOR_VERSION} EQUAL 1) AND (${Boost_MINOR_VERSION} EQUAL 54))
   message(SEND_ERROR "Boost version 1.54 is unsupported, more details are available here http://goo.gl/RrCFmA")
 endif()
diff --git a/ReleaseNotes.txt b/ReleaseNotes.txt
index 8822419f..69508d44 100644
--- a/ReleaseNotes.txt
+++ b/ReleaseNotes.txt
@@ -1,3 +1,9 @@
+Release notes 0.8.8
+
+- Fixed a bug with checkpoints behavior
+- UI improvements for daemon
+- Various updates from our forks
+
 Release notes 0.8.7
 
 - OSX support
diff --git a/src/cryptonote_core/blockchain_storage.cpp b/src/cryptonote_core/blockchain_storage.cpp
index 0e20b454..1787ec0a 100644
--- a/src/cryptonote_core/blockchain_storage.cpp
+++ b/src/cryptonote_core/blockchain_storage.cpp
@@ -372,7 +372,7 @@ bool blockchain_storage::rollback_blockchain_switching(std::list<block>& origina
   return true;
 }
 //------------------------------------------------------------------
-bool blockchain_storage::switch_to_alternative_blockchain(std::list<blocks_ext_by_hash::iterator>& alt_chain)
+bool blockchain_storage::switch_to_alternative_blockchain(std::list<blocks_ext_by_hash::iterator>& alt_chain, bool discard_disconnected_chain)
 {
   CRITICAL_REGION_LOCAL(m_blockchain_lock);
   CHECK_AND_ASSERT_MES(alt_chain.size(), false, "switch_to_alternative_blockchain: empty chain passed");
@@ -414,16 +414,19 @@ bool blockchain_storage::switch_to_alternative_blockchain(std::list<blocks_ext_b
     }
   }
 
-  //pushing old chain as alternative chain
-  BOOST_FOREACH(auto& old_ch_ent, disconnected_chain)
+  if(!discard_disconnected_chain)
   {
-    block_verification_context bvc = boost::value_initialized<block_verification_context>();
-    bool r = handle_alternative_block(old_ch_ent, get_block_hash(old_ch_ent), bvc);
-    if(!r)
+    //pushing old chain as alternative chain
+    BOOST_FOREACH(auto& old_ch_ent, disconnected_chain)
     {
-      LOG_ERROR("Failed to push ex-main chain blocks to alternative chain ");
-      rollback_blockchain_switching(disconnected_chain, split_height);
-      return false;
+      block_verification_context bvc = boost::value_initialized<block_verification_context>();
+      bool r = handle_alternative_block(old_ch_ent, get_block_hash(old_ch_ent), bvc);
+      if(!r)
+      {
+        LOG_ERROR("Failed to push ex-main chain blocks to alternative chain ");
+        rollback_blockchain_switching(disconnected_chain, split_height);
+        return false;
+      }
     }
   }
 
@@ -701,6 +704,22 @@ bool blockchain_storage::handle_alternative_block(const block& b, const crypto::
 {
   CRITICAL_REGION_LOCAL(m_blockchain_lock);
 
+  uint64_t block_height = get_block_height(b);
+  if(0 == block_height)
+  {
+    LOG_ERROR("Block with id: " << string_tools::pod_to_hex(id) << " (as alternative) have wrong miner transaction");
+    bvc.m_verifivation_failed = true;
+    return false;
+  }
+  if (!m_checkpoints.is_alternative_block_allowed(get_current_blockchain_height(), block_height))
+  {
+    LOG_PRINT_RED_L0("Block with id: " << id
+      << ENDL << " can't be accepted for alternative chain, block height: " << block_height
+      << ENDL << " blockchain height: " << get_current_blockchain_height());
+    bvc.m_verifivation_failed = true;
+    return false;
+  }
+
   //block is not related with head of main chain
   //first of all - look in alternative chains container
   auto it_main_prev = m_blocks_index.find(b.prev_id);
@@ -746,31 +765,28 @@ bool blockchain_storage::handle_alternative_block(const block& b, const crypto::
     block_extended_info bei = boost::value_initialized<block_extended_info>();
     bei.bl = b;
     bei.height = alt_chain.size() ? it_prev->second.height + 1 : it_main_prev->second + 1;
+
+    bool is_a_checkpoint;
+    if(!m_checkpoints.check_block(bei.height, id, is_a_checkpoint))
+    {
+      LOG_ERROR("CHECKPOINT VALIDATION FAILED");
+      bvc.m_verifivation_failed = true;
+      return false;
+    }
+
+    // Always check PoW for alternative blocks
+    m_is_in_checkpoint_zone = false;
     difficulty_type current_diff = get_next_difficulty_for_alternative_chain(alt_chain, bei);
     CHECK_AND_ASSERT_MES(current_diff, false, "!!!!!!! DIFFICULTY OVERHEAD !!!!!!!");
     crypto::hash proof_of_work = null_hash;
-    if(!m_checkpoints.is_in_checkpoint_zone(bei.height))
+    get_block_longhash(bei.bl, proof_of_work, bei.height);
+    if(!check_hash(proof_of_work, current_diff))
     {
-      m_is_in_checkpoint_zone = false;
-      get_block_longhash(bei.bl, proof_of_work, bei.height);
-
-      if(!check_hash(proof_of_work, current_diff))
-      {
-        LOG_PRINT_RED_L0("Block with id: " << id
-          << ENDL << " for alternative chain, have not enough proof of work: " << proof_of_work
-          << ENDL << " expected difficulty: " << current_diff);
-        bvc.m_verifivation_failed = true;
-        return false;
-      }
-    }else
-    {
-      m_is_in_checkpoint_zone = true;
-      if(!m_checkpoints.check_block(bei.height, id))
-      {
-        LOG_ERROR("CHECKPOINT VALIDATION FAILED");
-        bvc.m_verifivation_failed = true;
-        return false;
-      }
+      LOG_PRINT_RED_L0("Block with id: " << id
+        << ENDL << " for alternative chain, have not enough proof of work: " << proof_of_work
+        << ENDL << " expected difficulty: " << current_diff);
+      bvc.m_verifivation_failed = true;
+      return false;
     }
 
     if(!prevalidate_miner_transaction(b, bei.height))
@@ -792,22 +808,33 @@ bool blockchain_storage::handle_alternative_block(const block& b, const crypto::
     auto i_res = m_alternative_chains.insert(blocks_ext_by_hash::value_type(id, bei));
     CHECK_AND_ASSERT_MES(i_res.second, false, "insertion of new alternative block returned as it already exist");
     alt_chain.push_back(i_res.first);
-    //check if difficulty bigger then in main chain
-    if(m_blocks.back().cumulative_difficulty < bei.cumulative_difficulty)
+
+    if(is_a_checkpoint)
     {
       //do reorganize!
-      LOG_PRINT_GREEN("###### REORGANIZE on height: " << alt_chain.front()->second.height << " of " << m_blocks.size() -1  << " with cum_difficulty " << m_blocks.back().cumulative_difficulty
-        << ENDL << " alternative blockchain size: " << alt_chain.size() << " with cum_difficulty " << bei.cumulative_difficulty, LOG_LEVEL_0);
-      bool r = switch_to_alternative_blockchain(alt_chain);
+      LOG_PRINT_GREEN("###### REORGANIZE on height: " << alt_chain.front()->second.height << " of " << m_blocks.size() - 1 <<
+        ", checkpoint is found in alternative chain on height " << bei.height, LOG_LEVEL_0);
+      bool r = switch_to_alternative_blockchain(alt_chain, true);
       if(r) bvc.m_added_to_main_chain = true;
       else bvc.m_verifivation_failed = true;
       return r;
+    }else if(m_blocks.back().cumulative_difficulty < bei.cumulative_difficulty) //check if difficulty bigger then in main chain
+    {
+      //do reorganize!
+      LOG_PRINT_GREEN("###### REORGANIZE on height: " << alt_chain.front()->second.height << " of " << m_blocks.size() - 1 << " with cum_difficulty " << m_blocks.back().cumulative_difficulty
+        << ENDL << " alternative blockchain size: " << alt_chain.size() << " with cum_difficulty " << bei.cumulative_difficulty, LOG_LEVEL_0);
+      bool r = switch_to_alternative_blockchain(alt_chain, false);
+      if(r) bvc.m_added_to_main_chain = true;
+      else bvc.m_verifivation_failed = true;
+      return r;
+    }else
+    {
+      LOG_PRINT_BLUE("----- BLOCK ADDED AS ALTERNATIVE ON HEIGHT " << bei.height
+        << ENDL << "id:\t" << id
+        << ENDL << "PoW:\t" << proof_of_work
+        << ENDL << "difficulty:\t" << current_diff, LOG_LEVEL_0);
+      return true;
     }
-    LOG_PRINT_BLUE("----- BLOCK ADDED AS ALTERNATIVE ON HEIGHT " << bei.height
-      << ENDL << "id:\t" << id
-      << ENDL << "PoW:\t" << proof_of_work
-      << ENDL << "difficulty:\t" << current_diff, LOG_LEVEL_0);
-    return true;
   }else
   {
     //block orphaned
@@ -815,7 +842,6 @@ bool blockchain_storage::handle_alternative_block(const block& b, const crypto::
     LOG_PRINT_RED_L0("Block recognized as orphaned and rejected, id = " << id);
   }
 
-
   return true;
 }
 //------------------------------------------------------------------
diff --git a/src/cryptonote_core/blockchain_storage.h b/src/cryptonote_core/blockchain_storage.h
index 1ea5e29e..3a69d616 100644
--- a/src/cryptonote_core/blockchain_storage.h
+++ b/src/cryptonote_core/blockchain_storage.h
@@ -50,7 +50,7 @@ namespace cryptonote
       uint64_t already_generated_coins;
     };
 
-    blockchain_storage(tx_memory_pool& tx_pool):m_tx_pool(tx_pool), m_current_block_cumul_sz_limit(0), m_is_in_checkpoint_zone(false)
+    blockchain_storage(tx_memory_pool& tx_pool):m_tx_pool(tx_pool), m_current_block_cumul_sz_limit(0), m_is_in_checkpoint_zone(false), m_is_blockchain_storing(false)
     {};
 
     bool init() { return init(tools::get_default_data_dir()); }
@@ -186,7 +186,7 @@ namespace cryptonote
     std::atomic<bool> m_is_in_checkpoint_zone;
     std::atomic<bool> m_is_blockchain_storing;
 
-    bool switch_to_alternative_blockchain(std::list<blocks_ext_by_hash::iterator>& alt_chain);
+    bool switch_to_alternative_blockchain(std::list<blocks_ext_by_hash::iterator>& alt_chain, bool discard_disconnected_chain);
     bool pop_block_from_blockchain();
     bool purge_block_data_from_blockchain(const block& b, size_t processed_tx_count);
     bool purge_transaction_from_blockchain(const crypto::hash& tx_id);
diff --git a/src/cryptonote_core/checkpoints.cpp b/src/cryptonote_core/checkpoints.cpp
index 54c2f3a6..33a2d298 100644
--- a/src/cryptonote_core/checkpoints.cpp
+++ b/src/cryptonote_core/checkpoints.cpp
@@ -29,10 +29,11 @@ namespace cryptonote
     return !m_points.empty() && (height <= (--m_points.end())->first);
   }
   //---------------------------------------------------------------------------
-  bool checkpoints::check_block(uint64_t height, const crypto::hash& h) const
+  bool checkpoints::check_block(uint64_t height, const crypto::hash& h, bool& is_a_checkpoint) const
   {
     auto it = m_points.find(height);
-    if(it == m_points.end())
+    is_a_checkpoint = it != m_points.end();
+    if(!is_a_checkpoint)
       return true;
 
     if(it->second == h)
@@ -45,4 +46,25 @@ namespace cryptonote
       return false;
     }
   }
+  //---------------------------------------------------------------------------
+  bool checkpoints::check_block(uint64_t height, const crypto::hash& h) const
+  {
+    bool ignored;
+    return check_block(height, h, ignored);
+  }
+  //---------------------------------------------------------------------------
+  bool checkpoints::is_alternative_block_allowed(uint64_t blockchain_height, uint64_t block_height) const
+  {
+    if (0 == block_height)
+      return false;
+
+    auto it = m_points.upper_bound(blockchain_height);
+    // Is blockchain_height before the first checkpoint?
+    if (it == m_points.begin())
+      return true;
+
+    --it;
+    uint64_t checkpoint_height = it->first;
+    return checkpoint_height < block_height;
+  }
 }
diff --git a/src/cryptonote_core/checkpoints.h b/src/cryptonote_core/checkpoints.h
index 20014b1c..1bc055d9 100644
--- a/src/cryptonote_core/checkpoints.h
+++ b/src/cryptonote_core/checkpoints.h
@@ -16,6 +16,9 @@ namespace cryptonote
     bool add_checkpoint(uint64_t height, const std::string& hash_str);
     bool is_in_checkpoint_zone(uint64_t height) const;
     bool check_block(uint64_t height, const crypto::hash& h) const;
+    bool check_block(uint64_t height, const crypto::hash& h, bool& is_a_checkpoint) const;
+    bool is_alternative_block_allowed(uint64_t blockchain_height, uint64_t block_height) const;
+
   private:
     std::map<uint64_t, crypto::hash> m_points;
   };
diff --git a/src/cryptonote_core/checkpoints_create.h b/src/cryptonote_core/checkpoints_create.h
index 207cd236..fbe3c6b5 100644
--- a/src/cryptonote_core/checkpoints_create.h
+++ b/src/cryptonote_core/checkpoints_create.h
@@ -24,6 +24,7 @@ namespace cryptonote {
     ADD_CHECKPOINT(453537, "d17de6916c5aa6ffcae575309c80b0f8fdcd0a84b5fa8e41a841897d4b5a4e97");
     ADD_CHECKPOINT(462250, "13468d210a5ec884cf839f0259f247ccf3efef0414ac45172033d32c739beb3e");
     ADD_CHECKPOINT(468000, "251bcbd398b1f593193a7210934a3d87f692b2cb0c45206150f59683dd7e9ba1");
+    ADD_CHECKPOINT(480200, "363544ac9920c778b815c2fdbcbca70a0d79b21f662913a42da9b49e859f0e5b");
 
     return true;
   }
diff --git a/src/cryptonote_core/cryptonote_core.cpp b/src/cryptonote_core/cryptonote_core.cpp
index a09f25d3..b6bfa09c 100644
--- a/src/cryptonote_core/cryptonote_core.cpp
+++ b/src/cryptonote_core/cryptonote_core.cpp
@@ -502,7 +502,7 @@ namespace cryptonote
       LOG_PRINT_L0(ENDL << "**********************************************************************" << ENDL 
         << "The daemon will start synchronizing with the network. It may take up to several hours." << ENDL 
         << ENDL
-        << "You can set the level of process detailization by using command \"set_log <level>\", where <level> is either 0 (no details), 1 (current block height synchronized), or 2 (all details)." << ENDL
+        << "You can set the level of process detailization* through \"set_log <level>\" command*, where <level> is between 0 (no details) and 4 (very verbose)." << ENDL
         << ENDL
         << "Use \"help\" command to see the list of available commands." << ENDL
         << ENDL
diff --git a/src/cryptonote_core/miner.h b/src/cryptonote_core/miner.h
index da4578b0..84aa2788 100644
--- a/src/cryptonote_core/miner.h
+++ b/src/cryptonote_core/miner.h
@@ -4,7 +4,6 @@
 
 #pragma once 
 
-#include <boost/atomic.hpp>
 #include <boost/program_options.hpp>
 #include <atomic>
 #include "cryptonote_basic.h"
diff --git a/src/cryptonote_core/tx_extra.h b/src/cryptonote_core/tx_extra.h
index 8cff085d..37a04a41 100644
--- a/src/cryptonote_core/tx_extra.h
+++ b/src/cryptonote_core/tx_extra.h
@@ -11,6 +11,7 @@
 #define TX_EXTRA_TAG_PADDING                0x00
 #define TX_EXTRA_TAG_PUBKEY                 0x01
 #define TX_EXTRA_NONCE                      0x02
+#define TX_EXTRA_MERGE_MINING_TAG           0x03
 
 #define TX_EXTRA_NONCE_PAYMENT_ID           0x00
 
@@ -82,13 +83,62 @@ namespace cryptonote
     END_SERIALIZE()
   };
 
+  struct tx_extra_merge_mining_tag
+  {
+    struct serialize_helper
+    {
+      tx_extra_merge_mining_tag& mm_tag;
+
+      serialize_helper(tx_extra_merge_mining_tag& mm_tag_) : mm_tag(mm_tag_)
+      {
+      }
+
+      BEGIN_SERIALIZE()
+        VARINT_FIELD_N("depth", mm_tag.depth)
+        FIELD_N("merkle_root", mm_tag.merkle_root)
+      END_SERIALIZE()
+    };
+
+    size_t depth;
+    crypto::hash merkle_root;
+
+    // load
+    template <template <bool> class Archive>
+    bool do_serialize(Archive<false>& ar)
+    {
+      std::string field;
+      if(!::do_serialize(ar, field))
+        return false;
+
+      std::istringstream iss(field);
+      binary_archive<false> iar(iss);
+      serialize_helper helper(*this);
+      return ::serialization::serialize(iar, helper);
+    }
+
+    // store
+    template <template <bool> class Archive>
+    bool do_serialize(Archive<true>& ar)
+    {
+      std::ostringstream oss;
+      binary_archive<true> oar(oss);
+      serialize_helper helper(*this);
+      if(!::do_serialize(oar, helper))
+        return false;
+
+      std::string field = oss.str();
+      return ::serialization::serialize(ar, field);
+    }
+  };
+
   // tx_extra_field format, except tx_extra_padding and tx_extra_pub_key:
   //   varint tag;
   //   varint size;
   //   varint data[];
-  typedef boost::variant<tx_extra_padding, tx_extra_pub_key, tx_extra_nonce> tx_extra_field;
+  typedef boost::variant<tx_extra_padding, tx_extra_pub_key, tx_extra_nonce, tx_extra_merge_mining_tag> tx_extra_field;
 }
 
 VARIANT_TAG(binary_archive, cryptonote::tx_extra_padding, TX_EXTRA_TAG_PADDING);
 VARIANT_TAG(binary_archive, cryptonote::tx_extra_pub_key, TX_EXTRA_TAG_PUBKEY);
 VARIANT_TAG(binary_archive, cryptonote::tx_extra_nonce, TX_EXTRA_NONCE);
+VARIANT_TAG(binary_archive, cryptonote::tx_extra_merge_mining_tag, TX_EXTRA_MERGE_MINING_TAG);
diff --git a/src/cryptonote_protocol/cryptonote_protocol_handler.inl b/src/cryptonote_protocol/cryptonote_protocol_handler.inl
index 365d850e..b9f9a8fb 100644
--- a/src/cryptonote_protocol/cryptonote_protocol_handler.inl
+++ b/src/cryptonote_protocol/cryptonote_protocol_handler.inl
@@ -108,9 +108,12 @@ namespace cryptonote
       return true;
     }
 
-    LOG_PRINT_CCONTEXT_YELLOW("Sync data returned unknown top block: " << m_core.get_current_blockchain_height() << "->" << hshd.current_height 
-      << "[" << static_cast<int64_t>(hshd.current_height - m_core.get_current_blockchain_height()) << " blocks(" << (hshd.current_height - m_core.get_current_blockchain_height()) /720 << " days) behind] " << ENDL 
-      << "remote top: "  << hshd.top_id << "[" << hshd.current_height << "]" << ", set SYNCHRONIZATION mode", (is_inital ? LOG_LEVEL_0:LOG_LEVEL_1));
+    int64_t diff = static_cast<int64_t>(hshd.current_height) - static_cast<int64_t>(m_core.get_current_blockchain_height());
+    LOG_PRINT_CCONTEXT_YELLOW("Sync data returned unknown top block: " << m_core.get_current_blockchain_height() << " -> " << hshd.current_height
+      << " [" << std::abs(diff) << " blocks (" << diff / (24 * 60 * 60 / DIFFICULTY_TARGET) << " days) "
+      << (0 <= diff ? std::string("behind") : std::string("ahead"))
+      << "] " << ENDL << "SYNCHRONIZATION started", (is_inital ? LOG_LEVEL_0:LOG_LEVEL_1));
+    LOG_PRINT_L1("Remote top block height: " << hshd.current_height << ", id: " << hshd.top_id);
     context.m_state = cryptonote_connection_context::state_synchronizing;
     context.m_remote_blockchain_height = hshd.current_height;
     //let the socket to send response to handshake, but request callback, to let send request data after response
diff --git a/src/daemon/daemon_commands_handler.h b/src/daemon/daemon_commands_handler.h
index dca524f7..81d34b47 100644
--- a/src/daemon/daemon_commands_handler.h
+++ b/src/daemon/daemon_commands_handler.h
@@ -11,6 +11,7 @@
 #include "cryptonote_protocol/cryptonote_protocol_handler.h"
 #include "common/util.h"
 #include "crypto/hash.h"
+#include "version.h"
 
 
 class daemon_cmmands_handler
@@ -34,6 +35,7 @@ public:
     m_cmd_binder.set_handler("show_hr", boost::bind(&daemon_cmmands_handler::show_hr, this, _1), "Start showing hash rate");
     m_cmd_binder.set_handler("hide_hr", boost::bind(&daemon_cmmands_handler::hide_hr, this, _1), "Stop showing hash rate");
     m_cmd_binder.set_handler("save", boost::bind(&daemon_cmmands_handler::save, this, _1), "Save blockchain");
+    m_cmd_binder.set_handler("set_log", boost::bind(&daemon_cmmands_handler::set_log, this, _1), "set_log <level> - Change current log detalization level, <level> is a number 0-4");
   }
 
   bool start_handling()
@@ -54,6 +56,7 @@ private:
   std::string get_commands_str()
   {
     std::stringstream ss;
+    ss << CRYPTONOTE_NAME << " v" << PROJECT_VERSION_LONG << ENDL;
     ss << "Commands: " << ENDL;
     std::string usage = m_cmd_binder.get_usage();
     boost::replace_all(usage, "\n", "\n  ");
@@ -123,19 +126,34 @@ private:
       return false;
     }
     uint64_t start_index = 0;
+    uint64_t end_index = 0;
     uint64_t end_block_parametr = m_srv.get_payload_object().get_core().get_current_blockchain_height();
     if(!string_tools::get_xtype_from_string(start_index, args[0]))
     {
       std::cout << "wrong starter block index parameter" << ENDL;
       return false;
     }
-    if(args.size() >1 && !string_tools::get_xtype_from_string(end_block_parametr, args[1]))
+    if(args.size() >1 && !string_tools::get_xtype_from_string(end_index, args[1]))
     {
       std::cout << "wrong end block index parameter" << ENDL;
       return false;
     }
+    if (end_index == 0)
+    {
+      end_index = end_block_parametr;
+    }
+    if (end_index > end_block_parametr)
+    {
+      std::cout << "end block index parameter shouldn't be greater than " << end_block_parametr << ENDL;
+      return false;
+    }
+    if (end_index <= start_index)
+    {
+      std::cout << "end block index should be greater than starter block index" << ENDL;
+      return false;
+    }
 
-    m_srv.get_payload_object().get_core().print_blockchain(start_index, end_block_parametr);
+    m_srv.get_payload_object().get_core().print_blockchain(start_index, end_index);
     return true;
   }
   //--------------------------------------------------------------------------------
@@ -144,6 +162,33 @@ private:
     m_srv.get_payload_object().get_core().print_blockchain_index();
     return true;
   }
+
+  bool set_log(const std::vector<std::string>& args)
+  {
+    if(args.size() != 1)
+    {
+      std::cout << "use: set_log <log_level_number_0-4>" << ENDL;
+      return true;
+    }
+
+    uint16_t l = 0;
+    if(!string_tools::get_xtype_from_string(l, args[0]))
+    {
+      std::cout << "wrong number format, use: set_log <log_level_number_0-4>" << ENDL;
+      return true;
+    }
+
+    if(LOG_LEVEL_4 < l)
+    {
+      std::cout << "wrong number range, use: set_log <log_level_number_0-4>" << ENDL;
+      return true;
+    }
+
+    log_space::log_singletone::get_set_log_detalisation_level(true, l);
+
+    return true;
+  }
+
   //--------------------------------------------------------------------------------
   template <typename T>
   static bool print_as_json(T& obj)
diff --git a/src/miner/simpleminer.cpp b/src/miner/simpleminer.cpp
index 3af04954..a1c1ad5c 100644
--- a/src/miner/simpleminer.cpp
+++ b/src/miner/simpleminer.cpp
@@ -109,7 +109,7 @@ namespace mining
       if(!m_http_client.is_connected())
       {
         LOG_PRINT_L0("Connecting " << m_pool_ip << ":" << m_pool_port << "....");
-        if(!m_http_client.connect(m_pool_ip, m_pool_port, 1000))
+        if(!m_http_client.connect(m_pool_ip, m_pool_port, 20000))
         {
           LOG_PRINT_L0("Failed to connect " << m_pool_ip << ":" << m_pool_port << ", sleep....");
           epee::misc_utils::sleep_no_w(1000);
@@ -198,7 +198,7 @@ namespace mining
         LOG_PRINT_L0("Can't get new job! Disconnect and sleep....");
         m_http_client.disconnect();
         epee::misc_utils::sleep_no_w(1000);
-        break;
+        continue;
       }
       if (getjob_response.blob.empty() && getjob_response.target.empty() && getjob_response.job_id.empty())
       {
diff --git a/src/p2p/net_node.h b/src/p2p/net_node.h
index 794b9742..5cfdc765 100644
--- a/src/p2p/net_node.h
+++ b/src/p2p/net_node.h
@@ -146,6 +146,7 @@ namespace nodetool
     template<class t_callback>
     bool try_ping(basic_node_data& node_data, p2p_connection_context& context, t_callback cb);
     bool make_expected_connections_count(bool white_list, size_t expected_connections);
+    bool is_priority_node(const net_address& na);
 
     //debug functions
     std::string print_connections_container();
diff --git a/src/p2p/net_node.inl b/src/p2p/net_node.inl
index 399f4ae1..479f1f79 100644
--- a/src/p2p/net_node.inl
+++ b/src/p2p/net_node.inl
@@ -4,6 +4,8 @@
 
 #pragma once
 
+#include <algorithm>
+
 #include "version.h"
 #include "string_tools.h"
 #include "common/command_line.h"
@@ -405,10 +407,10 @@ namespace nodetool
           hsh_result = false;
           return;
         }
-        LOG_PRINT_CCONTEXT_L0(" COMMAND_HANDSHAKE INVOKED OK");
+        LOG_PRINT_CCONTEXT_L1(" COMMAND_HANDSHAKE INVOKED OK");
       }else
       {
-        LOG_PRINT_CCONTEXT_L0(" COMMAND_HANDSHAKE(AND CLOSE) INVOKED OK");
+        LOG_PRINT_CCONTEXT_L1(" COMMAND_HANDSHAKE(AND CLOSE) INVOKED OK");
       }
     }, P2P_DEFAULT_HANDSHAKE_INVOKE_TIMEOUT);
 
@@ -419,7 +421,7 @@ namespace nodetool
 
     if(!hsh_result)
     {
-      LOG_PRINT_CC_L0(context_, "COMMAND_HANDSHAKE Failed");
+      LOG_PRINT_CC_L1(context_, "COMMAND_HANDSHAKE Failed");
       m_net_server.get_config_object().close(context_.m_connection_id);
     }
 
@@ -510,36 +512,53 @@ namespace nodetool
     return connected;
   }
 
-  //-----------------------------------------------------------------------------------
+#define LOG_PRINT_CC_PRIORITY_NODE(priority, con, msg) \
+  do { \
+    if (priority) {\
+      LOG_PRINT_CC_L0(con, msg); \
+    } else {\
+      LOG_PRINT_CC_L1(con, msg); \
+    } \
+  } while(0)
+
   template<class t_payload_net_handler>
   bool node_server<t_payload_net_handler>::try_to_connect_and_handshake_with_new_peer(const net_address& na, bool just_take_peerlist, uint64_t last_seen_stamp, bool white)
   {
-    LOG_PRINT_L0("Connecting to " << string_tools::get_ip_string_from_int32(na.ip)  << ":" << string_tools::num_to_string_fast(na.port) << "(white=" << white << ", last_seen: " << (last_seen_stamp?misc_utils::get_time_interval_string(time(NULL) - last_seen_stamp):"never" ) << ")...");
+    LOG_PRINT_L1("Connecting to " << string_tools::get_ip_string_from_int32(na.ip)  << ":"
+        << string_tools::num_to_string_fast(na.port) << "(white=" << white << ", last_seen: "
+        << (last_seen_stamp?misc_utils::get_time_interval_string(time(NULL) - last_seen_stamp):"never")
+        << ")...");
 
     typename net_server::t_connection_context con = AUTO_VAL_INIT(con);
     bool res = m_net_server.connect(string_tools::get_ip_string_from_int32(na.ip),
       string_tools::num_to_string_fast(na.port),
       m_config.m_net_config.connection_timeout,
       con);
+
     if(!res)
     {
-      LOG_PRINT_L0("Connect failed to "
+      bool is_priority = is_priority_node(na);
+      LOG_PRINT_CC_PRIORITY_NODE(is_priority, con, "Connect failed to "
         << string_tools::get_ip_string_from_int32(na.ip)
         << ":" << string_tools::num_to_string_fast(na.port)
         /*<< ", try " << try_count*/);
       //m_peerlist.set_peer_unreachable(pe);
       return false;
     }
+
     peerid_type pi = AUTO_VAL_INIT(pi);
     res = do_handshake_with_peer(pi, con, just_take_peerlist);
+
     if(!res)
     {
-      LOG_PRINT_CC_L0(con, "Failed to HANDSHAKE with peer "
+      bool is_priority = is_priority_node(na);
+      LOG_PRINT_CC_PRIORITY_NODE(is_priority, con, "Failed to HANDSHAKE with peer "
         << string_tools::get_ip_string_from_int32(na.ip)
         << ":" << string_tools::num_to_string_fast(na.port)
         /*<< ", try " << try_count*/);
       return false;
     }
+
     if(just_take_peerlist)
     {
       m_net_server.get_config_object().close(con.m_connection_id);
@@ -557,6 +576,9 @@ namespace nodetool
     LOG_PRINT_CC_GREEN(con, "CONNECTION HANDSHAKED OK.", LOG_LEVEL_2);
     return true;
   }
+
+#undef LOG_PRINT_CC_PRIORITY_NODE
+
   //-----------------------------------------------------------------------------------
   template<class t_payload_net_handler>
   bool node_server<t_payload_net_handler>::make_new_connection_from_peerlist(bool use_white_list)
@@ -1095,5 +1117,10 @@ namespace nodetool
   {
     LOG_PRINT_L2("["<< net_utils::print_connection_context(context) << "] CLOSE CONNECTION");
   }
-  //-----------------------------------------------------------------------------------
+
+  template<class t_payload_net_handler>
+  bool node_server<t_payload_net_handler>::is_priority_node(const net_address& na)
+  {
+    return std::find(m_priority_peers.begin(), m_priority_peers.end(), na) != m_priority_peers.end();
+  }
 }
diff --git a/src/serialization/serialization.h b/src/serialization/serialization.h
index 2d78baf3..62ea78a3 100644
--- a/src/serialization/serialization.h
+++ b/src/serialization/serialization.h
@@ -79,8 +79,10 @@ inline bool do_serialize(Archive &ar, T &v)
     if (!r || !ar.stream().good()) return false; \
   } while(0);
 #define FIELDS(f) \
+  do { \
     bool r = ::do_serialize(ar, f); \
-    if (!r || !ar.stream().good()) return false;
+    if (!r || !ar.stream().good()) return false; \
+  } while(0);
 #define FIELD(f) \
   do { \
     ar.tag(#f); \
@@ -93,6 +95,12 @@ inline bool do_serialize(Archive &ar, T &v)
     ar.serialize_varint(f); \
     if (!ar.stream().good()) return false; \
   } while(0);
+#define VARINT_FIELD_N(t, f) \
+  do { \
+    ar.tag(t); \
+    ar.serialize_varint(f); \
+    if (!ar.stream().good()) return false; \
+  } while(0);
 
 namespace serialization {
   namespace detail
diff --git a/src/simplewallet/simplewallet.cpp b/src/simplewallet/simplewallet.cpp
index 919782ab..8b572a8e 100644
--- a/src/simplewallet/simplewallet.cpp
+++ b/src/simplewallet/simplewallet.cpp
@@ -228,8 +228,8 @@ bool simple_wallet::ask_wallet_create_if_needed()
   wallet_path = string_tools::trim(wallet_path);
 
   bool keys_file_exists;
-  bool wallet_file_exitst;
-  tools::wallet2::wallet_exists(wallet_path, keys_file_exists, wallet_file_exitst);
+  bool wallet_file_exists;
+  tools::wallet2::wallet_exists(wallet_path, keys_file_exists, wallet_file_exists);
 
   bool r;
   if(keys_file_exists)
@@ -238,7 +238,7 @@ bool simple_wallet::ask_wallet_create_if_needed()
     r = true;
   }else
   {
-    if(!wallet_file_exitst)
+    if(!wallet_file_exists)
     {
       std::cout << "The wallet doesn't exist, generating new one" << std::endl;
       m_generate_new = wallet_path;
diff --git a/src/version.h.in b/src/version.h.in
index c3d4157e..b9ba2bc1 100644
--- a/src/version.h.in
+++ b/src/version.h.in
@@ -1,4 +1,4 @@
 #define BUILD_COMMIT_ID "@VERSION@"
-#define PROJECT_VERSION "0.8.7"
-#define PROJECT_VERSION_BUILD_NO "58"
+#define PROJECT_VERSION "0.8.8"
+#define PROJECT_VERSION_BUILD_NO "65"
 #define PROJECT_VERSION_LONG PROJECT_VERSION "." PROJECT_VERSION_BUILD_NO "(" BUILD_COMMIT_ID ")"
diff --git a/src/wallet/wallet2.cpp b/src/wallet/wallet2.cpp
index e8d67eec..111b7611 100644
--- a/src/wallet/wallet2.cpp
+++ b/src/wallet/wallet2.cpp
@@ -455,14 +455,14 @@ void wallet2::generate(const std::string& wallet_, const std::string& password)
   store();
 }
 //----------------------------------------------------------------------------------------------------
-void wallet2::wallet_exists(const std::string& file_path, bool& keys_file_exists, bool& wallet_file_exitst)
+void wallet2::wallet_exists(const std::string& file_path, bool& keys_file_exists, bool& wallet_file_exists)
 {
   std::string keys_file, wallet_file;
   do_prepare_file_names(file_path, keys_file, wallet_file);
 
   boost::system::error_code ignore;
   keys_file_exists = boost::filesystem::exists(keys_file, ignore);
-  wallet_file_exitst = boost::filesystem::exists(wallet_file, ignore);
+  wallet_file_exists = boost::filesystem::exists(wallet_file, ignore);
 }
 //----------------------------------------------------------------------------------------------------
 bool wallet2::prepare_file_names(const std::string& file_path)
diff --git a/src/wallet/wallet2.h b/src/wallet/wallet2.h
index edbf31f2..ecd9e51e 100644
--- a/src/wallet/wallet2.h
+++ b/src/wallet/wallet2.h
@@ -144,7 +144,7 @@ namespace tools
       a & m_payments;
     }
 
-    static void wallet_exists(const std::string& file_path, bool& keys_file_exists, bool& wallet_file_exitst);
+    static void wallet_exists(const std::string& file_path, bool& keys_file_exists, bool& wallet_file_exists);
 
   private:
     bool store_keys(const std::string& keys_file_name, const std::string& password);
diff --git a/tests/performance_tests/cn_slow_hash.h b/tests/performance_tests/cn_slow_hash.h
new file mode 100644
index 00000000..ec001326
--- /dev/null
+++ b/tests/performance_tests/cn_slow_hash.h
@@ -0,0 +1,45 @@
+// Copyright (c) 2012-2013 The Cryptonote developers
+// Distributed under the MIT/X11 software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#pragma once
+
+#include "crypto/crypto.h"
+#include "cryptonote_core/cryptonote_basic.h"
+
+class test_cn_slow_hash
+{
+public:
+  static const size_t loop_count = 10;
+
+#pragma pack(push, 1)
+  struct data_t
+  {
+    char data[13];
+  };
+#pragma pack(pop)
+
+  static_assert(13 == sizeof(data_t), "Invalid structure size");
+
+  bool init()
+  {
+    if (!epee::string_tools::hex_to_pod("63617665617420656d70746f72", m_data))
+      return false;
+
+    if (!epee::string_tools::hex_to_pod("bbec2cacf69866a8e740380fe7b818fc78f8571221742d729d9d02d7f8989b87", m_expected_hash))
+      return false;
+
+    return true;
+  }
+
+  bool test()
+  {
+    crypto::hash hash;
+    crypto::cn_slow_hash(&m_data, sizeof(m_data), hash);
+    return hash == m_expected_hash;
+  }
+
+private:
+  data_t m_data;
+  crypto::hash m_expected_hash;
+};
diff --git a/tests/performance_tests/main.cpp b/tests/performance_tests/main.cpp
index 2ad503b8..72ee2ca6 100644
--- a/tests/performance_tests/main.cpp
+++ b/tests/performance_tests/main.cpp
@@ -8,6 +8,7 @@
 // tests
 #include "construct_tx.h"
 #include "check_ring_signature.h"
+#include "cn_slow_hash.h"
 #include "derive_public_key.h"
 #include "derive_secret_key.h"
 #include "generate_key_derivation.h"
@@ -56,6 +57,8 @@ int main(int argc, char** argv)
   TEST_PERFORMANCE0(test_derive_public_key);
   TEST_PERFORMANCE0(test_derive_secret_key);
 
+  TEST_PERFORMANCE0(test_cn_slow_hash);
+
   std::cout << "Tests finished. Elapsed time: " << timer.elapsed_ms() / 1000 << " sec" << std::endl;
 
   return 0;
diff --git a/tests/unit_tests/checkpoints.cpp b/tests/unit_tests/checkpoints.cpp
new file mode 100644
index 00000000..0d7bd4de
--- /dev/null
+++ b/tests/unit_tests/checkpoints.cpp
@@ -0,0 +1,140 @@
+// Copyright (c) 2012-2013 The Cryptonote developers
+// Distributed under the MIT/X11 software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include "gtest/gtest.h"
+
+#include "cryptonote_core/checkpoints.cpp"
+
+using namespace cryptonote;
+
+
+TEST(checkpoints_is_alternative_block_allowed, handles_empty_checkpoins)
+{
+  checkpoints cp;
+
+  ASSERT_FALSE(cp.is_alternative_block_allowed(0, 0));
+
+  ASSERT_TRUE(cp.is_alternative_block_allowed(1, 1));
+  ASSERT_TRUE(cp.is_alternative_block_allowed(1, 9));
+  ASSERT_TRUE(cp.is_alternative_block_allowed(9, 1));
+}
+
+TEST(checkpoints_is_alternative_block_allowed, handles_one_checkpoint)
+{
+  checkpoints cp;
+  cp.add_checkpoint(5, "0000000000000000000000000000000000000000000000000000000000000000");
+
+  ASSERT_FALSE(cp.is_alternative_block_allowed(0, 0));
+
+  ASSERT_TRUE (cp.is_alternative_block_allowed(1, 1));
+  ASSERT_TRUE (cp.is_alternative_block_allowed(1, 4));
+  ASSERT_TRUE (cp.is_alternative_block_allowed(1, 5));
+  ASSERT_TRUE (cp.is_alternative_block_allowed(1, 6));
+  ASSERT_TRUE (cp.is_alternative_block_allowed(1, 9));
+
+  ASSERT_TRUE (cp.is_alternative_block_allowed(4, 1));
+  ASSERT_TRUE (cp.is_alternative_block_allowed(4, 4));
+  ASSERT_TRUE (cp.is_alternative_block_allowed(4, 5));
+  ASSERT_TRUE (cp.is_alternative_block_allowed(4, 6));
+  ASSERT_TRUE (cp.is_alternative_block_allowed(4, 9));
+
+  ASSERT_FALSE(cp.is_alternative_block_allowed(5, 1));
+  ASSERT_FALSE(cp.is_alternative_block_allowed(5, 4));
+  ASSERT_FALSE(cp.is_alternative_block_allowed(5, 5));
+  ASSERT_TRUE (cp.is_alternative_block_allowed(5, 6));
+  ASSERT_TRUE (cp.is_alternative_block_allowed(5, 9));
+
+  ASSERT_FALSE(cp.is_alternative_block_allowed(6, 1));
+  ASSERT_FALSE(cp.is_alternative_block_allowed(6, 4));
+  ASSERT_FALSE(cp.is_alternative_block_allowed(6, 5));
+  ASSERT_TRUE (cp.is_alternative_block_allowed(6, 6));
+  ASSERT_TRUE (cp.is_alternative_block_allowed(6, 9));
+
+  ASSERT_FALSE(cp.is_alternative_block_allowed(9, 1));
+  ASSERT_FALSE(cp.is_alternative_block_allowed(9, 4));
+  ASSERT_FALSE(cp.is_alternative_block_allowed(9, 5));
+  ASSERT_TRUE (cp.is_alternative_block_allowed(9, 6));
+  ASSERT_TRUE (cp.is_alternative_block_allowed(9, 9));
+}
+
+TEST(checkpoints_is_alternative_block_allowed, handles_two_and_more_checkpoints)
+{
+  checkpoints cp;
+  cp.add_checkpoint(5, "0000000000000000000000000000000000000000000000000000000000000000");
+  cp.add_checkpoint(9, "0000000000000000000000000000000000000000000000000000000000000000");
+
+  ASSERT_FALSE(cp.is_alternative_block_allowed(0, 0));
+
+  ASSERT_TRUE (cp.is_alternative_block_allowed(1, 1));
+  ASSERT_TRUE (cp.is_alternative_block_allowed(1, 4));
+  ASSERT_TRUE (cp.is_alternative_block_allowed(1, 5));
+  ASSERT_TRUE (cp.is_alternative_block_allowed(1, 6));
+  ASSERT_TRUE (cp.is_alternative_block_allowed(1, 8));
+  ASSERT_TRUE (cp.is_alternative_block_allowed(1, 9));
+  ASSERT_TRUE (cp.is_alternative_block_allowed(1, 10));
+  ASSERT_TRUE (cp.is_alternative_block_allowed(1, 11));
+
+  ASSERT_TRUE (cp.is_alternative_block_allowed(4, 1));
+  ASSERT_TRUE (cp.is_alternative_block_allowed(4, 4));
+  ASSERT_TRUE (cp.is_alternative_block_allowed(4, 5));
+  ASSERT_TRUE (cp.is_alternative_block_allowed(4, 6));
+  ASSERT_TRUE (cp.is_alternative_block_allowed(4, 8));
+  ASSERT_TRUE (cp.is_alternative_block_allowed(4, 9));
+  ASSERT_TRUE (cp.is_alternative_block_allowed(4, 10));
+  ASSERT_TRUE (cp.is_alternative_block_allowed(4, 11));
+
+  ASSERT_FALSE(cp.is_alternative_block_allowed(5, 1));
+  ASSERT_FALSE(cp.is_alternative_block_allowed(5, 4));
+  ASSERT_FALSE(cp.is_alternative_block_allowed(5, 5));
+  ASSERT_TRUE (cp.is_alternative_block_allowed(5, 6));
+  ASSERT_TRUE (cp.is_alternative_block_allowed(5, 8));
+  ASSERT_TRUE (cp.is_alternative_block_allowed(5, 9));
+  ASSERT_TRUE (cp.is_alternative_block_allowed(5, 10));
+  ASSERT_TRUE (cp.is_alternative_block_allowed(5, 11));
+
+  ASSERT_FALSE(cp.is_alternative_block_allowed(6, 1));
+  ASSERT_FALSE(cp.is_alternative_block_allowed(6, 4));
+  ASSERT_FALSE(cp.is_alternative_block_allowed(6, 5));
+  ASSERT_TRUE (cp.is_alternative_block_allowed(6, 6));
+  ASSERT_TRUE (cp.is_alternative_block_allowed(6, 8));
+  ASSERT_TRUE (cp.is_alternative_block_allowed(6, 9));
+  ASSERT_TRUE (cp.is_alternative_block_allowed(6, 10));
+  ASSERT_TRUE (cp.is_alternative_block_allowed(6, 11));
+
+  ASSERT_FALSE(cp.is_alternative_block_allowed(8, 1));
+  ASSERT_FALSE(cp.is_alternative_block_allowed(8, 4));
+  ASSERT_FALSE(cp.is_alternative_block_allowed(8, 5));
+  ASSERT_TRUE (cp.is_alternative_block_allowed(8, 6));
+  ASSERT_TRUE (cp.is_alternative_block_allowed(8, 8));
+  ASSERT_TRUE (cp.is_alternative_block_allowed(8, 9));
+  ASSERT_TRUE (cp.is_alternative_block_allowed(8, 10));
+  ASSERT_TRUE (cp.is_alternative_block_allowed(8, 11));
+
+  ASSERT_FALSE(cp.is_alternative_block_allowed(9, 1));
+  ASSERT_FALSE(cp.is_alternative_block_allowed(9, 4));
+  ASSERT_FALSE(cp.is_alternative_block_allowed(9, 5));
+  ASSERT_FALSE(cp.is_alternative_block_allowed(9, 6));
+  ASSERT_FALSE(cp.is_alternative_block_allowed(9, 8));
+  ASSERT_FALSE(cp.is_alternative_block_allowed(9, 9));
+  ASSERT_TRUE (cp.is_alternative_block_allowed(9, 10));
+  ASSERT_TRUE (cp.is_alternative_block_allowed(9, 11));
+
+  ASSERT_FALSE(cp.is_alternative_block_allowed(10, 1));
+  ASSERT_FALSE(cp.is_alternative_block_allowed(10, 4));
+  ASSERT_FALSE(cp.is_alternative_block_allowed(10, 5));
+  ASSERT_FALSE(cp.is_alternative_block_allowed(10, 6));
+  ASSERT_FALSE(cp.is_alternative_block_allowed(10, 8));
+  ASSERT_FALSE(cp.is_alternative_block_allowed(10, 9));
+  ASSERT_TRUE (cp.is_alternative_block_allowed(10, 10));
+  ASSERT_TRUE (cp.is_alternative_block_allowed(10, 11));
+
+  ASSERT_FALSE(cp.is_alternative_block_allowed(11, 1));
+  ASSERT_FALSE(cp.is_alternative_block_allowed(11, 4));
+  ASSERT_FALSE(cp.is_alternative_block_allowed(11, 5));
+  ASSERT_FALSE(cp.is_alternative_block_allowed(11, 6));
+  ASSERT_FALSE(cp.is_alternative_block_allowed(11, 8));
+  ASSERT_FALSE(cp.is_alternative_block_allowed(11, 9));
+  ASSERT_TRUE (cp.is_alternative_block_allowed(11, 10));
+  ASSERT_TRUE (cp.is_alternative_block_allowed(11, 11));
+}