how do I change the SDK version to 30?

[Anke]

@AUGUSTO_MARTIN_FERNA

can you create an application with sdk 28 to generate a folder in internal storage?

Yes you can. Since WRITE_EXTERNAL_STORAGE permission can also be requested with targetSdkVersion = 30 on Android 9 devices, you can use the

• Canvas component or the
• TaifunFile extension or best the
• FileTools extension from @ vknow360 for that
  (since the latter has its own method "CreateDirectory").

Btw, with internal storage you mean most likely "external storage", see here.