please see the HISTORY file included in the Release, but a summary
consists of:
* Change encoding function signature to prevent misuse
* Change "contrib/tsearch2" to avoid unsafe use of INTERNAL function
results
* Repair race condition between relation extension and VACUUM
This could theoretically have caused loss of a page's worth of
freshly-inserted data, although the scenario seems of very low
probability. There are no known cases of it having caused more than
an Assert failure.
Security: http://www.postgresql.org/about/news.315