I revert back to 1.4.14 but now all client showing offline?

all clients showing offline how can i fix it?

Are your clients currently on 2.X while your server is back to 1.X?

If yes, that is your issue. Newer clients cannot be on older servers - at least from what I remember.

Before it was communicating. I installed 1.4.14 on windows xp and 2.x on
windows 7 and 10 this my previous setup

Before new client communicating with 1.4.14 server

2.X clients can only communicate with a 2.X server; 1.X clients can communicate with both 1.X and 2.X servers.

(I’ll need confirmation since I am not sure, but I thought that was how it was)
In other words - your clients can be at or below your server, but not above it.

Also, you could go into each client and remove the server_idents.txt and restart the service before you do anything else and see if that will allow them to rejoin.

Thats was sure for me 2.x clients communicating with 1.4.14 server. Any its
star t working automatically.

If they are not working yet, have you tried getting rid of the server_idents.txt from each client?

C:\Program Files\UrBackup -> delete server_idents.txt
services.msc -> restart UrBackup service