Where ever a db version is mentioned you should expect the same version for the GI also . As you no doubt know the GI version must always be equal to or greater than the DB version.
Good logical answer.Yes DB version can be <= GI version.
I want oracle to specify GI veriosn to have proof of supported GI versions in the MOS doc.888828.1
somewhere can we get that proof.
Main reason is i want to upgrade 188.8.131.52 GI to 18c .
And we have 184.108.40.206.6 exadata version.I know we cannot upgrade GI to 18c on this.
So wanted proof.
The OEDA release notes/README should mention when a new version of Grid/DB is supported.
I don't think this specific information is mentioned anywhere. As Robin mentioned, you need to infer this from the DB versions that are supported as listed with a specific Exadata software release.
GI Software is independent from the Exadata Software (like Storage Server or DB Node Software).
GI Software must be the highest Version in your Cluster & Database environment.
So never use a higher RDBMS Software as the GI Software.
You can check your Installation via "exachk" and there you found a recommendation
Maximum Availability Architecture (MAA) Scorecard
Found version Recommended versions
But what is your real problem?
If my understanding of 888828.1 is correct, you need Exadata server software 18.x to be able to run any piece of 18c Oracle software (including the GI bits). Also, see the section named "Oracle Database 18c Release 220.127.116.11.0" - it explicitly mentions a release dependency between GI and Exadata versions.
Anyway, since you are an Oracle employee: Why don't you just ask the PMs?