The following issues have been discovered with StoreFront 1906.1.0.27 concerning upgrading and uninstalling:

1. If you attempt to upgrade to StoreFront 1906 from StoreFront 3.7, or from a version of StoreFront that was upgraded from StoreFront 3.7, the upgrade fails. (WSP-4386)
2. Uninstallation of StoreFront 1906 appears to succeed, but traces of the StoreFront installation are left behind in C:\program files\citrix\receiver storefront\*. Attempts to reinstall StoreFront fail, indicating that StoreFront is still installed. (WSP-4399)

A new build 1906.2.0.34 of stand-alone StoreFront metainstaller (CitrixStoreFront-x64.exe) is available from https://www.citrix.com/downloads/storefront/product-software/storefront-1906.html.  Citrix recommends that you use StoreFront 1906.2.0.34 instead of StoreFront 1906.1.0.27, especially for upgrading from a previous installation of StoreFront.

If you already used 1906.1.0.27 to upgrade a server that has—or previously had—StoreFront 3.7 installed on it, and the upgrade failed, restore StoreFront to a functional state from a backup (physical backup or VM snapshot), then rerun the upgrade using the updated StoreFront build 1906.2.0.34.

If you have a storefront version 1906.1.0.31 which was a respin for 1906.1.027, it was not part of any ISO, please ask support to provide a download link for you by opening a Citrix case.