Hi Bartosz Jarmuż 

Yes.  Go to the Translation Memories View and use the Upgrade TM routine.  This may help, it's a little old but the process hasn't really changed much:

Hi Bartosz,

As I've investigated, the Sdl.LanguagePlatform.TranslationMemoryApi expose a method named Export(string fileName, bool overriteExisting) which can help you in the convert process. (see below print screen where i have access that specific method).

With kind regards,

Florentina Lucia Caputa

Hi Bartosz,

After the discussion with a developer that has worked on the tm conversion, he gave me a project which can inspire you on the conversion process. I have added the project on the Sdl Community GitHub: https://github.com/sdl/Sdl-Community

This project is named Sdl.Community.UpLiftAutomationV4.  There is a class TmExport.cs in the solution which can guide you how to export tmw files (see also print screen)

With kind regards,

Florentina

Good day, Florentina.
If i try to convert tmw translation memory with that process, i have error message

Sdl.LanguagePlatform.Core.LanguagePlatformException: The specified file is not a valid translation memory.
at Sdl.LanguagePlatform.TranslationMemoryApi.AbstractLocalTranslationMemory.get_Setup()
at Sdl.LanguagePlatform.TranslationMemoryApi.FileBasedTranslationMemoryLanguageDirection.get_SourceLanguage()
at TMExporter.ExportTMXFile(String tmPath, String exportFilePath)

and more interesting, i dont have any errors after constructor
var exporter = new TranslationMemoryExporter(_tm.LanguageDirection);

but have it on stage
exporter.Export(exportFullPath, true)

or if i try to get source-target languages
string source = _tm.LanguageDirection.SourceLanguage;

When i convert sdltm with this, no any problem, converting is made correct.