language not available for older versions

Where to find language packs for older versions? I have to use 5.15.2 as it is dictated by the company, but the current file is made for 5.15.4 and is not working with the previous version.

Just change the version number in the download link.

For example German language pack for 5.15.2 is:
https://winscp.net/translations/dll/5.15.2/de.zip