Read no further unless you care about the MySQL database dumps in the database_files directory on the FTP site.
A couple of people (many thanks Jeff and Jakob) found errors in the the release 20 MySQL database dumps: a small number of new mature sequences were not linked to their hairpin precursors, and the ends of a smaller number of old mature sequences were off by 1. The table affected was mirna_pre_mature. If you’re using these dumps you will probably want to grab the fixed version from the FTP site (timestamp 17/7/2013). You might notice other files in that directory with the same new timestamp — feel free to grab those too, but you are much less likely to care about those (the changes are either cosmetic or updated links to other resources). The FASTA format sequence files, the EMBL format data file, and all other data dumps were unaffected by these bugs.
Apologies for any inconvenience.