The 7.0.20 release includes bug fixes and the following new features compared to version 7.0.19 including:
- JSP files with dependencies in JARs are no longer recompiled on every access thereby improving performance.
- Update to version 1.1.22 of the native component of the AJP and HTTP APR/native connectors.
- Update to Commons Daemon 1.0.7.
- Converted unit tests to JUnit 4.
Full details of these changes, and all the other changes, are available in the Tomcat 7 changelog