Blobcache issues

I had some weird problem with images in Sharepoint 2013.
Issues were for example

• Updated images didn't work, old images still showed for clients. 
• Change imageproperties didn't work either
• Changing website logo didn't work

BlobCache quickly became as suspect, so we tried to flush the blobcache the proper way with flushBlobCache.ps1 but the folders in the blobcache-directory didn't get recreated.
Expected behaviour is when flushblob has run on farm, the folder under siteID in blob-directory will get a new created date and new name.
For me, they just left the old folder without change on certain farm-members.

After searching for a official solution I landed on my own fix which was as follows

1. Redirect trafik from webfrontend or do this during servicewindow
2. Update url and run setBlobDisabled.ps1 (or disable blob manually in web.config)
3. This will cause a reset to Application Pool and blobfolder will stop updating change.bin file in blob temp-directory
4. Rename or delete folder with SiteID, for example E:\Blob\14\354006434 to 354006434_old
5.  Update url and run setBlobEnabled.ps1
6. Problem solved.

 

Checking Dotnet version on server

I needed to check running dotnet version on a few servers to verify support for TLS 1.2
I used script below, which I though was easy to update and using hash-tables in an effective way.