Magnolia 4.5 reached end of life on June 30, 2016. This branch is no longer supported, see End-of-life policy.
Take a backup of your system before you install a module. Uninstalling a module is not as simple as removing the .jar file. Modules add and change configuration and may change content. Try new modules in a test environment first. A module consist of a JAR file and may include dependent JAR files. Modules are responsible for updating their own content and configuration across versions. Be sure to keep only one version of each module and its dependencies.
To install a module:
WEB-INF/lib
directory. The location of this directory depends on the application server./webapps/magnoliaAuthor/WEB-INF/lib
/server/default/deploy/magnoliaPublic/WEB-INF/lib
Repeat the steps for each author and public instance.