I have a wordpress theme i purchased a while ago and i dont think its beeen supported by its aurthor anymore. the wordpress version currently using is 3.9.2 is their any changes in 4.0 that would require the code for the WordPress theme to be changed to so it works smoothly?
WordPress usually changes very little with regards to theme tags in a core update, that means if the theme is working well with 3.9.2 it should continue to do so with 4.0 as well. That said, we have no idea how the theme have been made, or what functions it uses. The best option here, is that you create a test site (a duplicate one). Upgrade it to the latest version and see how it goes. If all works out well.. carry out the up-gradation process on the actual site. REMEMBER TO BACK UP EVERYTHING BEFORE MAKING ANY CHANGES. (I suggest at least 2 backup copies)
I think theme will work fine you can upgrade the wordpress version anytime. But please make sure you got the backup first...
Thanks for the advice guys, I will test it 1st on a test site and if it works ill back up and update my actual site.
Most themes will work in wordpress 4.0. However, I came across one whose backoffice media library was broken after updating wordpress. Fortunately, the author quickly launched a new update for the theme that fixed that. Do as you said, a test site. Hopefully, everything goes well! If you need any help, let us know.