- In earlier TeamCity versions Maven was executed by invoking the 'mvn' shell script. You could specify some parameters in MAVEN_OPTS and some in UI. Maven build runner created its own MAVEN_OPT by concatenating these two (
%MAVEN_OPTS%+jvmArgs). In this case, if some parameter was specified twice - in MAVEN_OPTS and in UI, only the one specified in MAVEN_OPTS was effective. Starting with TeamCity 6.5 Maven runner forms direct java command. While this approach solves many different problems, it also means that MAVEN_OPTS isn't effective anymore and all JVM command line parameters should be specified in build runner settings instead of MAVEN_OPTS.
- Those who had to manually setup surefire XML reporting for Maven release builds in TeamCity 6.0.x because otherwise tests weren't reported, now can forget about that. Since TeamCity 6.5 surefire tests run by release:prepare or release:perform goals are automatically detected. So don't forget to switch surefire XML reporting off in the build configuration settings to avoid double-reporting!
Email sending settings
Please check email sending settings are working correctly after upgrade (via Test connection on Administration > Server Configuration > EMail Notifier). If no authentication is needed, make sure login and password fields are blank. Non-blank fields may cause email sending errors if SMTP server is not expecting authentication requests.
Open API Changes
Several return types have changes in TeamCity open API, so plugins might need recompilation against new TeamCity version to continue working.
Also, some API was deprecated and will be discontinued in later releases. It is recommended to update plugins not to use deprecated API.
See also Open API Changes