Hi Today, that class declares only one field LUCENE_MAIN_VERSION, which is changed between releases. When 3.1 was released, it was set to "3.1" and now it is set to "3.2".
I think that it will be good if we have a constants per version that can be found in a SegmentInfo.getVersion(), so that we can easily compare a certain SI.getVersion() w/ some release. We already have the following versions: "2.x" - for any pre-3.0 indexes "3.0" "3.1" "3.2" (in 3x, unreleased) "4.0" (in trunk, unreleased) This will be useful for LUCENE-2921 as well. Shai
