Under steam there is version 1.01 available since 29.06.2021 with additional languages (German, Polish and French). What about the Gog-Version?

The 1.49 GOG version is the steam v1.01a version.

However I am not sure about the languages. There is no in-game selection of a language. Note that I am using the offline installers. It may be possible to configure the language from Galaxy and/or when installing the game. Looking at the steam forums it also appears that versions language is changed from the steam settings and not in-game.

I just tested it and the language support work for the offline installer (and I guess for Galaxy aswell, but I do not use that).

If you use the offline installer, to change the language you have to (re-)install the game and select "Options" in the install setup menu. There you can pick between English, German, Polish, French. In my case even my save game was still availible and changing the language between English and German via reinstalling the entire game worked.
Since I only did a quick test with the German version (which was fine besides minor spelling issues) I can not really tell about the actual quality of the other translations, but the Devs stated on Steam that the translations are more of a "Beta" version.
One last thing: Only the text is translated, voice is still only English.

any chance to include spanish languaje?