Dear Juan Maria.
Originally I installed my cas server under debian 10 in version 6.2.0.
I make the upgrade from this release without problem since today by doing this :
I make change in the file "gradle.properties", and change the "cas.version" variable with the new release version. Then I run
# gradlew clean
&
# gradlew clean copyCasConfiguration build
I restart the tomcat and it's ok.
Regards