LedgerSMB version numbers are in the form of Major.Minor.Patch-Optional Tag. So for example, the current 1.9 development release is 1.9.28-dev and the production release is 1.9.27
An increment in the major release number can mean significant architectural, Application Programmer Interface (API), functional, or usage changes. It is expected that an upgrade to a new Major version is going to be planned and tested by the user organization before upgrading.
An increment in the minor release number may indicate changes to APIs , interfaces, user instructions, etc. But these changes are not expected to have major impact and should require minor planning and testing. Often small impact enhancements are back-patched to previous Minor versions as patches.
Increments in the Patch number represent bug fixes, security improvements, or enhancements that do not break existing functionality, usage, or APIs. These changes are expected to be applied to an installation as soon as possible.
Common values include dev, beta, or alpha. Typically, these are only used internally by the LedgerSMB developers.