SOLUTION
In folder
C:\Users\<username>\AppData\Roaming\Quest Software\Toad for DB2 <version>\Templates\CodeTemplates
There are files with name like
CodeTemplate.SQL.DB2.merge.xml
These files can be copied to the same location of the new version. These files are generated only if there is any change otherwise, there are no files generated.
If the Toad for DB2 is installed as a virtual application, the path to the can be something like this:
C:\Users\<username>\AppData\Roaming\Microsoft\AppV\Client\VFS\4A14CE2F-5B71-426C-C4AB-6A0ABF3147C1\AppData\Quest Software\Toad for DB2 6.1\Templates\CodeTemplates