Joomla 2.5 Compatibility
Open Source Matters, the organisation behind Joomla! released the version 2.5.0 of Joomla 10 days back. The new release cycle introduced by OSM last year caused much discussion among the open source community and well to be quite frank, the new 2.5.0 has added more fuel to the "discussions". But it is not as bad as it looks. No really, it is not bad at all.
The changes started when OSM introduced Joomla 1.6 last year and then few months later announced that it was being deprecated and recommended to switch to 1.7. OSM had maintained Joomla 1.5 for about 3 years then and the previous version, the original fork from Mambo (Joomla 1.0) was supported close to 4 years. When Joomla 1.6 was released it was thought that the same pattern would continue; It didn't Joomla 1.6 was deprecated about 7 months after it was introduced. When OSM announced that it was on a 6 month release cycle, more mayhem followed.
The point was however this. 1.6 was never a long term production release. It was meant as a base release for the developers and implementers to get accustomed to 1.7 and later releases. Unfortunately some did not see this notice, or was too enthralled by the latest release with all the funky features and decided to jump in. Fortunately enough there weren't much differences between the two (http://docs.joomla.org/Potential_backward_compatibility_issues_in_Joomla_1.7_and_Joomla_Platform_11.1) (well we at Kulendra.Net, did come across some problems but that's because we decided to override some core Joomla classes, it's not really their fault :) ) and well things worked on ok
Few months back, OSM did announce that it was working on a new release 1.8 and that it would be a natural successor to 1.7. Meaning that everything that worked on 1.7 will automatically work on 1.8. This sort of pacified the initial outrage, but then when OSM announced 2.5.0, thing started going crazy again. What most people did not understand was that 2.5 was 1.8 renamed. It was renamed after an opinion poll and due to the fact that it is going to be a long term release supported for 18 months.
As far as compatibility is concerned, all extensions that worked under 1.7 will continue to work in 2.5.0. We at Kulendra.Net have added notes to all our extensions that are compatible with both 1.7 and 2.5. To be quite honest, we didn't have to do anything other than just re-test all the extensions.
However, this does not mean that everything is going great. One of the users who posted at Joomla forums was stating how hard it is to make customers understand the difference between the various versions. This particular one has been asking him why was his site being built on an outdated version (1.7 compared to 2.5). Regardless of whatever the reason OSM has, it doesn't make it sensible for a large number of users who are not technical. However as far as the balance is concerned, it still does more good than bad.And for all you know, you actually got single click upgrade to Joomla 2.5 :)