Starting with SanteDB 2.x, versions are differentiated between a technology preview version and a hardened/LTS version using the minor build number. Minor builds which are even numbered are considered stable and no API changes are permitted (2.0.x, 2.2.x, 2.4.x, etc.). Builds with odd numbered minor versions are considered technology preview builds (2.1.x, 2.3.x, 2.5.x). CTP releases are suitable for use for developers, pilots, etc. and each revision within the minor build should be relatively compatible with one another.