GRANT used with IDENTIFIED BY didn't take effect until privileges were flushed.
Name change of some variables in SHOW STATUS.
Fixed problem with ORDER BY with 'only index' optimization when there were multiple key definitions for a used column.
DATE and DATETIME columns are now up to 5 times faster than before.
INSERT DELAYED can be used to let the client do other things while the server inserts rows into a table.
LEFT JOIN USING (col1,col2) didn't work if one used it with tables from 2 different databases.
LOAD DATA LOCAL INFILE didn't work in the Unix version because of a missing file.
Fixed problems with VARCHAR/BLOB on very short rows (< 4 bytes); error 127 could occur when deleting rows.
Updating BLOB/TEXT through formulas didn't work for short (< 256 char) strings.
When you did a GRANT on a new host, mysqld could die on the first connect from this host.
Fixed bug when one used ORDER BY on column name that was the same name as an alias.
Added BENCHMARK(loop_count,expression) function to time expressions.