This article describes the issue when upgrade to NPM 10.0 and you receive the following error:
Errors on this webpage might cause it to work incorrectly
WebForm_PostBackOptions' is undefined
NPM version 10.0
This is a known website building issue. It needs a full Windows Update.
This is probably an IE caching issue where some JS files are not loaded because browser thought they're cached.
This issue is resolved in the next release of Orion NPM 11.0 and later . Please continue upgrade to a higher version.