We upgraded to version 5 in 2013. It really didn't seem that long ago, but now I am alpha testing version 6. We will have 18 months after the official release of version 6 to fully upgrade. There is not yet an official release date as I am still in alpha testing. Fenrir and I can recreate anything that we designed for the forum. The developer of the forum's shop is redoing 12,000 lines of code so that the shop will be functional in version 6.
Visually, version 6 has a very different feel, but we will be free to make changes and adjustments. Here is some information I have from the higher powers regarding changes you may notice immediately.
Badges Due to the overall lack of interest, we have opted to remove badges as a full featured system. The good news here is that if you've ever purchased a badge for yourself or had a badge gifted to you, you will keep that badge, and it will still be displayed in your user profile. However, going forward the badge store will be shut down, and badge functionality (gifting, badge actions, etc.) will not be integrated into v6. To reiterate, badges that you own will display in your user profile in v6.
Calendar The calendar is one of the least-used features on our platform. You want to know how unpopular it is? In the last month, visits to the calendar accounted for around 0.02% of all traffic across all forums. There are half a dozen pages in the admin area that get more traffic than the calendar. Yet, despite this tiny amount of traffic, the calendar results in a large amount of complexity, from both a design and implementation standpoint. As a result, we've made a decision to remove the calendar as an integrated part of our forum platform. We're developing a plugin that will allow you to integrate Google Calendar directly into your forum.