If you are updating from a version 7.x-2.x prior to 7.x-2.70 then be sure to see the NOTE for 7.x-2.70!
Version 7.x-2.66 has just the security patch, in case you're not ready to update to the current version yet, but should do so ASAP.
Please note that you are using very old code that is missing bug fixes.
Update to the current release ASAP, because only the current release is covered by the security advisory policy!
If you are updating from a version 7.x-2.x prior to 7.x-2.70 then be sure to see the NOTE for 7.x-2.70!
Version 7.x-2.66 has just the security patch, in case you're not ready to update to the current version yet, but should do so ASAP.
NOTE: A lot of fixes have accumulated over past years—be sure to test this version thoroughly if you're updating from 7.x-2.65, and please report any issues that you may find.