Create a Dynamic Group template for the older ESET version, to find your computers with the old version installed. Example template values below. Then create a Dynamic Group that uses that template to find the computers with the old agent. You could even create an agent install task to run in that dynamic group daily. Or just push the new agent install version to all or some in that group manually. You can create a similar dynamic group for the newer agent version to see the computers with the new version installed.
Installed software . Application vendor = ESET, spol. s r.o. Installed software . Application version contains 7.2.2