You can find all the resolved issues in our tracker. (login, type "fixed in" and choose the version)
TeamCity 2020.1 released
...
Lakhnau 2020.1 RC (build 78421) Release Notes, resolved issues
Lakhnau 2020.1 EAP3 (build 78205) Release Notes, resolved issues
Lakhnau 2020.1 EAP2 (build 78003) Release Notes, resolved issues
Lakhnau 2020.1 EAP1 (build 77859) Release Notes, resolved issues
TeamCity 2019.2 released
...