MyBB

MyBB 1.4 has been out for over 8 months. During this time we have had a security audit done and we believe that the 1.4 series is the safest yet. So upgrading should not worry you one bit. When we first released 1.4 we only planned to continue support for 6 months but continued support due to the sizeable amount of people that still used the 1.2 series.

Support for the 1.2 series will end on June 1st, 2009 - making it 9 months of support after the release of the 1.4 series. For those of you who are still operating boards with 1.2 we urge you to upgrade to the latest 1.4 release and seek help if needed before June 1st.

Some links that may be of use to you:
Downloads - To obtain the latest MyBB release
[Wiki: Database_Backup] (Broken link, head over to docs.mybb.com instead) - Always important if something goes wrong. Also be sure to backup all your files.
[Wiki: Upgrading] (Broken link, head over to docs.mybb.com instead) - Standard upgrading procedure details.

After June 1st, 2009, the 1.2 support forums will be moved to the read-only archive.

It is important to note that we will still provide vulnerability patches for the 1.2 series until December 31st, 2009.

Full blog post and discussion