Changes 5.5.13:
* InnoDB Storage Engine: If the server crashed while an XA transaction was
  prepared but not yet committed, the transaction could remain in the system
  after restart, and cause a subsequent shutdown to hang.
* InnoDB Storage Engine: Similar problem to the foreign key error in bug
  11831040 / 60196 / 60909, but with a different root cause and occurring on
  Mac OS X. With the setting lower_case_table_names=2, inserts into InnoDB
  tables covered by foreign key constraints could fail after a server restart.
* Partitioning: The internal get_partition_set() function did not take into
  account the possibility that a key specification could be NULL in some cases.
* Partitioning: When executing a row-ordered retrieval index merge, the
  partitioning handler used memory from from that allocated for the table,
  rather than that allocated to the query, causing table object memory not to
  be freed until the table was closed.
* Replication: A spurious error malformed binlog: it does not contain any
  Format_description_log_event... was generated when mysqlbinlog was invoked
  using --base64-output=decode-row and --start-position=pos, where pos is a
  point in the binary log past the format description log event. However, there
  is nothing unsafe about not printing the format description log event, so the
  error has been removed for this case.
* Replication: Typographical errors appeared in the text of several replication  error messages. (The word ���position��� was misspelled as ���postion���.)
* Assignments to NEW.var_name within triggers, where var_name had a BLOB or
  TEXT type, were not properly handled and produced incorrect results.
* XA COMMIT could fail to clean up the error state if it discovered that the
  current XA transaction had to be rolled back. Consequently, the next XA
  transaction could raise an assertion when it checked for proper cleanup of
  the previous transaction.
* An internal client macro reference was removed from the client_plugin.h
  header file. This reference made the file unusable.
* The server consumed memory for repeated invocation of some stored procedures,
  which was not released until the connection terminated.
* The server did not check for certain invalid out of order sequences of XA
  statements, and these sequences raised an assertion.
* With the conversion from GNU autotools to CMake for configuring MySQL, the
  USE_SYMDIR preprocessor symbol was omitted. This caused failure of symbolic
  links (described at Section 7.11.3.1, ���Using Symbolic Links���).


(adam)