It does appear for other series we include the ~12.04.1 bit in the uname -a output:
Linux kowtow-b64 5.0.0-21-generic #22~18.04.1-Ubuntu SMP Thu Jul 4 17:25:00 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux
But it is likely best to use /proc/version_signature in preference to this.
It does appear for other series we include the ~12.04.1 bit in the uname -a output:
Linux kowtow-b64 5.0.0-21-generic #22~18.04.1-Ubuntu SMP Thu Jul 4 17:25:00 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux
But it is likely best to use /proc/version_ signature in preference to this.