What release of the full version of Easytrieve is compatible with Common Services v15?
CA Easytrieve release 6.4
Common Services 14.1 and earlier contained CA Easytrieve release 6.4 for the Easytrieve option.
Common Services 15.0 delivers as a separate installation CA Easytrieve release 11.6.
As long as there is a license for the full CA Easytrieve product, then all is fine to upgrade to Common Services 15.0, independent of the release of CA Easytrieve.
It is also encouraged to please upgrade your CA Easytrieve to release 11.6 as soon as possible. But, this is not reliant on your release of Common Services. This was announced December 14, 2020: End of Support Date for CA Easytrieve release 6.4 is December 15, 2021: