https://help.tallysolutions.com/docs/ts9rel54/ts9/release_5.5.3.htm

Release Notes for Tally.Server 9 Release 5.5.3

Licensing

‚óŹ Tally.Server 9 Release 5.5.2 and earlier could not recognise later versions of Tally Gateway Server. This issue is resolved.

Now, Tally.Server 9 can recognise release 5.x and above versions of the Tally Gateway Server.