From version 0.80 onward, Transmission's peer-id is formatted in Azureus' style with one digit for the major version, two digits for the minor version and one character to denote a stable release (`0`), nightly build (`Z`) or prerelease beta (`X`). For example:
Rationale: This differentiates between official and unofficial releases in a way which is easy for trackers to detect with simple string comparison. An official release (`-TR1330-`) is lexicographically smaller than its post-release unsupported versions (`-TR133Z-` and `-TR133X-`), which in turn are lexicographically smaller than the next official release (`-TR1340-`).
Before 0.80, versions of Transmission used two digits for the major version and two for the minor version. For example, `-TR0072-` was Transmission 0.72.