The D compiler labels sets of types, variables, functions, constants, and translators corresponding to a particular software release using a version string. A version string is a period-delimited sequence of decimal integers of the form “x” (a Major release), “x.y” (a Minor release), or “x.y.z” (a Micro release). Versions are compared by comparing the integers from left to right. If the leftmost integers are not equal, the string with the greater integer is the greater (and therefore more recent) version. If the leftmost integers are equal, the comparison proceeds to the next integer in order from left to right to determine the result. All unspecified integers in a version string are interpreted as having the value zero during a version comparison.

The DTrace version strings correspond to Sun's standard nomenclature for interface versions, as described in attributes ( 5 ) . A change in the D programming interface is accompanied by a new version string. The following table summarizes the version strings used by DTrace and the likely significance of the corresponding DTrace software release.

In general, each new version of the D programming interface will provide a superset of the capabilities offered by the previous version, with the exception of any Obsolete interfaces that have been removed.