Maybe its me, but a lot of contributions I see I have difficulties with, purely because of the version they are implemented on.
Its possible I misunderstand the versioning system, but I see some inherent problems with the way some contributions are labelled.
I see osCommerce as a platform with differing versions, reliant on dates with regards to version numbers. For example, the CVS tree, being the most up to date. Now, I have seen various contributions explain that their contributions work with CVS 2.2, although will you may have difficulties with later versions after the next update (not to 2.3, maybe just a few weeks if the CVS tree is altered slightly).
Now, this is an inherent problem I believe in writing contributions. If a module is being written, that relies on no other files outside of the standard module/ and languages/ directories, I imagine there should be no difficulties.
But since contributions frequently make changes to pieces of code, they also become reliant on the same variable names the same files etc.
These contributions should still work, but they don't.
Now maybe I'm biased because I installed MS2, but I've looked at other projects and they do not seem affected in the same way, largely because they used a Milestone edition to make adaptations and add-ons for.
One thing is clear, a lot of contributions are not clearly labelled as being for use for MS2 or MS1. At the moment all contributions seem to be labelled as CVS2.2 which is not helpful (since sometimes a date is needed to indicate whether it is certain to work or not even if you are using the CVS version), also the date in some projects, seems to alternate between american date format mm/dd/yyyy and dd/mm/yyyy which would make it confusing other than the fact the new items are at the top. Consistancy is the key!
Anyway, thats my five pounds worth. If I'm wrong about any of this I apologise, but I won't be slighted if you point out any innaccuracy on my point. As well, this is not meant to be critical of those who have written contributions. Contributions are (IMHO) the most important thing about osCommerce. Tailoring the application to a persons individual needs.