Based on MySQL 5.5.37, including all the bug fixes in it, Percona Server 5.5.37-35.0 is now the current stable release in the 5.5 series. All of Percona‘s software is open-source and free, all the details of the release can be found in the 5.5.37-35.0 milestone at Launchpad.
Percona Server debug packages were not built for the previous releases. Bug fixed #1298352.
Queries that no longer exceed long_query_time were written to the slow query log if they matched the previous long_query_time value when slow_query_log_use_global_control variable was set to all. Bug fixed #1016991.
Previous implementation of the log_slow_rate_type set to query with log_slow_rate_limit feature would log every nth query deterministically instead of each query having a 1/n probability to get logged. Fixed by randomly selecting the queries to be logged instead of logging every nth query. Bug fixed #1287650.
Percona Server source files were referencing Maatkit instead of Percona Toolkit. Bug fixed #1174779.
Maximum allowed value for log_slow_rate_limit was ULONG_MAX (ie. either 4294967295 or 18446744073709551615, depending on the platform). As it was unreasonable to configure the slow log for every four billionth session/query, new maximum allowed value is set to 1000. Bug fixed #1290714.
Other bugs fixed: #1272732.