The LTS releases extend the support period we traditionally offered (12 months) to a longer period, both to reduce the frequency of upgrades, and to provide increasing stability during the life of each LTS release (through regular patch releases). All LTS releases are supported for 18-24 months from the date the release is designated as an LTS release. This is the way it's been since the beginning, as described in our documentation since December of 2020: https://www.dotcms.com/docs/latest/release-support-lifecycle#SupportPeriod
Unfortunately, several months ago an error was introduced in the dates displayed in our documentation by someone who's no longer with dotCMS, and we didn't see the error until recently. So, we recently changed the 5.3.8 EOL dates back to what they have actually always been - which is June 2022.
We apologize for the dates that were incorrectly showing a later EOL. But unfortunately we're just not able to fully support releases for longer than 18-24 months. The simple truth is that the main code base continues to change, and once we get 18 months or more past the original release date, we can't backport most (or sometimes any) fixes without risking creating new issues. Since the core purpose of the LTS releases is to provide improved reliability for our customers, we can't afford to risk that reliability in order to continue backporting fixes several years past the original release date.
However, please understand that when we say a release is past the EOL, that doesn't mean that you can't receive any support on it. Customers with access to the dotCMS Helpdesk can always ask for and receive support on any dotCMS release, even ones that are past EOL. And everyone can always use this forum (which is monitored by both very experienced dotCMS users and senior dotCMS staff). When an LTS release is past EOL, it means that we will stop delivering patch releases for that version. This means that a release past the EOL will no longer receive proactive fixes, and may not receive fixes for things like critical security vulnerabilities, should any be found.
With all that said, we will be extending the EOL date for 5.3.8 LTS through the end of September, and we may extend it a little further after that. We always reserve the right to extend the EOL date for any release if we believe that we can continue to support it without affecting the stability of the release. And ultimately, we plan to continue to fully support 5.3.8 LTS until we designate the next LTS release, which should be some time between September and December.
Finally, it's important to note - we strongly recommend that any time you upgrade, you upgrade to the latest LTS release. This will ensure that the version you upgraded to will be supported for the longest time before you'll need to upgrade again. If you recently upgraded to 5.3.8 LTS, or you're in the process of upgrading to 5.3.8 LTS, then you're upgrading to a version that's already more than 18 months old; since we're unable to fully support releases more than 24 months at the outside, we just can't recommend that as best practice.