OSDOCS4193:typo fix

Author: skopacz1

modules/migration-compatibility-guidelines.adoc

@@ -33,7 +33,7 @@ Legacy {mtc-version} operator: Install manually with the `operator.yml` file.
 This cluster cannot be the control cluster.
 ====
 
-|{mtc-short} {mtc-version}.z
+|{mtc-short} {mtc-version}._z_
 
 Install with OLM, release channel `release-v1.7`
 |===