Install OLAT as described in the installation chapter but DON'T RUN 'ant dbsetup'!! We recommend to move your existing installation from PATH_TO_YOUR_OLAT/olat3 to PATH_TO_YOUR_OLAT/olat5.2.x and install the 5.2.x package as your new PATH_TO_YOUR_OLAT/olat3. All user data is located in the olatdata directory which should not be located in the PATH_TO_YOUR_OLAT/olat3. The olatdata directory and the database won't be changed when installing the new code.

#cd PATH_TO_YOUR_OLAT
#rm olat (if olat is a symlink, otherwise: mv olat3 olat5.2.0)
#unzip OLAT-5.2.0.zip
#ln -s OLAT-5.2.0-FINAL-XXXXX olat
#cd olat
#cp build.properties.default build.properties
#vi build.properties
#ant install

Update your database manually according to PATH_TO_YOUR_OLAT/olat3/database/alter_5_1_0_to_5_2_0.sql

Now start tomcat.