Also I could state that changes occurring in the version number usually occur when new features are added to the forum code. So, from 3.3 to 3.4 there were a lot of new features added, which is what usually occurs when we change 3.x to 3.x+1. Bug fixes usually are denoted by changes in the minor version number. For example, from 3.4.01 to 3.4.02 bug fixes are added to the code. Usually when a new version comes out (a change in 3.x, for example), changes between minor versions occur more frequently, since there are a bit more bugs to be corrected. So, usually we go faster from 3.x to 3.x.01 to 3.x.02). The criteria to release a new minor version is up to the Dev Team, but I guess they do it when they think there are enough or relevant enough changes to justify such a release. Hope this helps.