May 27, 2009 (SVN revision: 161402)
* First 2.2.21 release
* Added support for Best-Hit algorithm.
* Added support for -in_msa psiblast option. 
* Performance improvements and bug fixes to subject soft masking feature (note:
  the file format for the files containing the masking information has changed
  in a non-backwards compatible way).
* Changed command line option to specify single soft masking algorithm to mask
  BLAST databases from -mask_subjects to -db_soft_mask.
* Masked FASTA and subject masks can be obtained via blastdbcmd.
* Improved error messages when makeblastdb processes masking information.
* Bug fixes in tabular output for translated searches.
* Bug fixes to makeblastdb.
* Bug fixes to search strategies and megablast.
* Bug fixes to XML output.
* Bug fixes and performance improvements to multi-threaded execution.
* Bug fixes to lower case masking in blastx.
* Bug fixes to ungapped searches.
* Added support for smaller lookup tables for small queries.
* Added support for partial sequence fetching during traceback.
* Fixed the 2-hit algorithm so that no overlap between two hits is allowed.
* Implemented a new method to compute effective observations and new
entropy-based method to compute column-specific pseudocounts in PSI-BLAST.
* Remote BLAST database data loader is used as a fallback if local BLAST 
databases cannot be found.
* Bug fixes, improved error messages, and support for ASN.1 input in 
makeblastdb.
* Bug fixes and performance improvements to subject masking feature.
* Added the update_blastdb.pl script
* Updated BLAST+ user manual with documentation about configuring BLAST, 
automatic resolution of sequence identifiers, and a description of how the 
BLAST databases are searched.

November 3, 2008 (SVN revision: 144798)
* First 2.2.19 release
* Made sequence ID/title display uniform in sequence filtering applications.
* Fixed incorrect display of filtering options in XML output.
* Fixed handling of empty sequences in BLAST input. 
* Fixed negative strand handling for tblastn/tblastx.

October 14, 2008 (SVN revision: 143045)
* Added update_blastdb.pl script to distribution of BLAST+ command line 
  applications.
* Changed a few PSI-BLAST constants for pseudo-counts.
* Bug fix in blastdbcmd to distinguish non-redundant sequence titles.
* Bug fix to display BLAST database information remotely from outside NCBI for
  XML output. 

September 24, 2008 (SVN revision: 141260) 
* Fix to prevent initial seed extension from going beyond context boundary.
* Improvements to reduce memory usage when query splitting is applied.
* Print the accession and version for blastdbcmd's %a output format.
* gilists/negative gilists are not saved in search strategies or supported in
  remote blast searches.
* legacy_blast.pl fixed for MacOSX, as well as extended support for megablast
  formatting options (-D, -f).
* Enhancements to Mac installer to add installation path to user's PATH.
* ASN.1 output is now of type Seq-annot.
* -lcase_masking option now applies to subject sequences as well as queries.
* Bug fix for creation of masked databases with non-redundant sequences that use
  a BLAST database as its data source.
* Bug fix for merging masking locations.

August 21, 2008 (SVN revision: 138123)
* First internal release