28,659 questions
Hello,
Yes, you can directly upgrade to Version 21H2 via ISO file and that's an offline upgrade usually.
Refer this step-by-step guide:
https://www.kapilarya.com/how-to-upgrade-to-windows-10-using-iso-file
Let us know if this helps!
Note: Included link in this reply refers to blog post by a trusted Microsoft MVP.