Major or minor. Changes to the major or minor portion of the version number indicate an incompatible change. Under this convention then, version 220.127.116.11 would be considered incompatible with version 18.104.22.168. Examples of an incompatible change would be a change to the types of some method parameters or the removal of a type or method altogether. Build. The Build number is typically used to distinguish between daily builds or smaller compatible releases. Revision. Changes to the revision number are typically reserved for an incremental build needed to fix a particular bug. You'll sometimes hear this referred to as the "emergency bug fix" number in that the revision is what is often changed when a fix to a specific bug is shipped to a customer.