From my understanding, the most important thing is that the Major version matches the servers major version (i.e. 10.5 in your case).
I have often used an older version of tabcmd with a newer version of server (i.e. 10.5 server and 10.2 tabcmd).
So my advice: Make sure that you are running tabcmd in the same version as the server, if you have 10.5.2 and the server is 10.5.3 that should be no problem, but to be 100% bulletproof, make tabcmd match the server minor version as well.
Thank you for your input. I had a similar understanding, however in the past we faced problems where some of our tabcmd commands would run in 9.1 but not in 9.0. This is why I was concerned. I think I will try to be 100% bulletproof :-)
9.1 and 9.0 are different major versions.
9.0.1 and 9.0.2 are same major version (9.0) but different minor version (1 and 2)