I have written this " /=\?UTF\-8\?B\?zrs=\?=/ " and i tested it in regex editors and its working for the text string " =?UTF-8?B?zrs=?= ".
But when i put it in proxmox Mail Filter -> What objects its not working,
Does it need another format?
The string =?UTF-8?B?zrs=?= is for a Greek...