This release fixes a security vulnerability. Sites are urged to upgrade immediately after reading the security announcement:

    * SA-2008-046 - Drupal core - Session fixation

In addition to this security vulnerability, the following bugs have been fixed in the 5.9 release:

    * #281042 by schuyler1d. Render blocks before CSS and JS header generation.
    * #232433 by Damien Tournoud. Use non-localized date for RSS.
    * #281494 by beeradb. Code style.
    * #252580 by Robert Douglass, Gerhard Killesreiter, flobruit: avoid division by zero, when all search weights are set to 0.
    * #252921 by David_Rothstein and agentrickard: remove unused join, which caused column type compatibility problems with postgresql; improves postgresql compatibility.
    * #128846 by takashi, chx, bdragon, wedge, salvis, Shiny: rewritten queries on PostreSQL need to have matching DISTINCT ON and ORDER BY expressions
    * #280934. Make sure session is always regenerated.

(adrianp)