Waths about the i18n texts of the framework. When I import a new version of the framework, Will this texts be overwritten, when I made changes on it?
When you import a new version of the framework in developer, you get a dialog that asks if you want to import the i18n data.
By default it will insert new keys and also update existing (changed) ones.
But there is also a checkbox that makes it possible to only allow inserts:
[attachment=0]i18n.png[/attachment]