dot net app (on Linux) broke - "Forbidden" error - needs roll-forward

The issue turned out to be -

1. some dot net commands like
   dotnet --version
   would not work due to mismatch between Ubuntu and Microsoft tracks for dotnet. Fixed with help from this blog post,
   
   # first remove everything
   sudo apt remove dotnet*
    sudo apt remove aspnetcore*
    sudo apt remove netstandard*
   sudo rm /etc/apt/sources.list.d/microsoft-prod.list
    sudo apt update
   sudo apt upgrade
   
   Then as in the original install link
   https://www.syncfusion.com/blogs/post/hosting-multiple-asp-net-core-apps-in-ubuntu-linux-server-using-apache.aspx
   
   wget https://packages.microsoft.com/config/ubuntu/22.04/packages-microsoft-prod.deb -O packages-microsoft-prod.deb
   sudo dpkg -i packages-microsoft-prod.deb
   sudo apt-get update; sudo apt-get install -y apt-transport-https && sudo apt-get update && sudo apt-get install -y aspnetcore-runtime-7.0
   
   dotnet --list-runtimes
   # pinned as per the troubleshooting blog post
   sudo nano /etc/apt/preferences
   Package: dotnet-* aspnetcore-* netstandard-*
   Pin: origin "packages.microsoft.com"
   Pin-Priority: 999
   
   #set /etc/dotnet/install_location to /usr/share/dotnet.
   
   #Then fix the missing DOTNET_ROOT environment variable and add (re-add?) that path #to the PATH environment variable in ~/.bashrc
   sudo apt update
   sudo apt install dotnet-sdk-7.0
   
   
2. Next, the particular dot net app was targeting 7.0.0 - and that framework was not being found, since it had been updated to 7.0.400 or 7.0.10 (depending on whether it was the runtime or the sdk. Running from the commandline gave this error,
   
   dotnet ourdll.dll
   
   
   Framework: 'Microsoft.NETCore.App', version '7.0.0' (x64)

   .NET location: /usr/share/dotnet/

   
   

   No frameworks were found.
   
   
   and
   /usr/bin/dotnet --info
   
   
   Host:
     Version:      7.0.10
     Architecture: x64
     Commit:       a6dbb800a4
    
   Informed the developers,
   
   

   it is targeting dot net 7.0.0 and yesterday an update was rolled out to dot net, and the dot net is currently at 7.0.10
   
   You would need to target using roll-forward - so that updates to dot net do not break the app -
   Select which .NET version to use - .NET | Roll forward
    
   Instead of targeting 7.0.0 alone, you need to retarget the app using 7.0.* as mentioned in the above link.
   
   They seem to have fixed it by adding the "rollForward": "LatestMinor" in the runtimeconfig.json file.
   
   
3. As suggested by the developers, disabled automatic updates, so that this issue won't happen for the next major upgrade of dotnet. Set up apticron to inform me of pending updates. Set up the "mail" command using ssmtp as in this earlier post. 
   
   
   https://www.makeuseof.com/disable-automatic-updates-in-ubuntu
   
   
   Ubuntu Manpage: apticron - Generate a mail listing packages which are pending an upgrade
   
   
   apt - How to make my server email me when there are security updates? - Ask Ubuntu 
   
   sudo nano /etc/apt/apt.conf.d/20auto-upgrades
   # set both to 0
   sudo apt install apticron
   cd /etc/apticron
   more README
   sudo cp '/usr/lib/apticron/apticron.conf' . -v
   sudo nano apticron.conf
   # set it with
   NOTIFY_NO_UPDATES="1"
   # so that I'll know if it's working, by emailing every day.