Make the program compatible with NET 9

There is a thin client written in C# that performs two main functions:

• Accept a payment request and send it to the POS terminal, then report the result to the backend.
• Accept a print request from the backend and send it to the printer.

Communication with the backend occurs via REST API and websocket.

The problem is - after updating Windows on users' computers, the program stopped launching, reporting incompatibility with NET 9. It is necessary either to rebuild it making it compatible with NET9 or to set up an automatic installation of NET5 as a temporary solution. If you see another option - that is also possible.

The task is quite urgent and a solution needs to be implemented as soon as possible.

You can familiarize yourself with the client via AnyDesk

Please propose a budget

P.S. There are also some requests for improvements to the client, so collaboration could be long-term