upon installation of the most up to date 4.7.1, I couldn’t start the Protonvpn

TLDR, reinstall proton-vpn-gnome-desktop, fixes the issues.

below are my terminal history,

similar to the bug report from reddit:

https://www.reddit.com/r/ProtonVPN/comments/1gjhaoi/protonvpn_update_on_linux_mint_213_fails_to_start/ (front end: https://redlib.privacyredirect.com/r/ProtonVPN/comments/1gjhaoi/protonvpn_update_on_linux_mint_213_fails_to_start/)

$ protonvpn-app 

Traceback (most recent call last):
  File "/usr/bin/protonvpn-app", line 33, in <module>
    sys.exit(load_entry_point('proton-vpn-gtk-app==4.7.1', 'console_scripts', 'protonvpn-app')())
  File "/usr/lib/python3/dist-packages/proton/vpn/app/gtk/__main__.py", line 35, in main
    controller = Controller.get(executor, exception_handler)
  File "/usr/lib/python3/dist-packages/proton/vpn/app/gtk/controller.py", line 64, in get
    executor.submit(controller.initialize_vpn_connector).result()
  File "/usr/lib/python3.10/concurrent/futures/_base.py", line 458, in result
    return self.__get_result()
  File "/usr/lib/python3.10/concurrent/futures/_base.py", line 403, in __get_result
    raise self._exception
  File "/usr/lib/python3/dist-packages/proton/vpn/app/gtk/controller.py", line 97, in initialize_vpn_connector
    self._connector = await self._api.get_vpn_connector()
  File "/usr/lib/python3/dist-packages/proton/vpn/core/api.py", line 63, in get_vpn_connector
    self._vpn_connector = await VPNConnector.get(
  File "/usr/lib/python3/dist-packages/proton/vpn/core/connection.py", line 94, in get
    await connector.initialize_state()
  File "/usr/lib/python3/dist-packages/proton/vpn/core/connection.py", line 251, in initialize_state
    state = await self._get_initial_state()
  File "/usr/lib/python3/dist-packages/proton/vpn/core/connection.py", line 240, in _get_initial_state
    current_connection = await self._get_current_connection()
  File "/usr/lib/python3/dist-packages/proton/vpn/core/connection.py", line 218, in _get_current_connection
    backend_class = Loader.get("backend", persisted_parameters.backend)
  File "/usr/lib/python3/dist-packages/proton/loader/loader.py", line 129, in get
    raise RuntimeError(f"Loader: couldn't find an acceptable implementation for {type_name}.")
RuntimeError: Loader: couldn't find an acceptable implementation for backend.

$ sudo apt install proton-vpn-gnome-desktop

[sudo] password for user: 
Reading package lists... Done
Building dependency tree... Done
Reading state information... Done
The following additional packages will be installed:
  python3-proton-vpn-network-manager
The following NEW packages will be installed:
  proton-vpn-gnome-desktop python3-proton-vpn-network-manager
0 upgraded, 2 newly installed, 0 to remove and 0 not upgraded.
Need to get 31.1 kB of archives.
After this operation, 207 kB of additional disk space will be used.
Do you want to continue? [Y/n] y
Get:1 https://repo.protonvpn.com/debian stable/main all python3-proton-vpn-network-manager all 0.9.4 [28.4 kB]
Get:2 https://repo.protonvpn.com/debian stable/main all proton-vpn-gnome-desktop all 0.8.0 [2,628 B]
Fetched 31.1 kB in 1s (24.5 kB/s)                    
Selecting previously unselected package python3-proton-vpn-network-manager.
(Reading database ... 235378 files and directories currently installed.)
Preparing to unpack .../python3-proton-vpn-network-manager_0.9.4_all.deb ...
Unpacking python3-proton-vpn-network-manager (0.9.4) ...
Selecting previously unselected package proton-vpn-gnome-desktop.
Preparing to unpack .../proton-vpn-gnome-desktop_0.8.0_all.deb ...
Unpacking proton-vpn-gnome-desktop (0.8.0) ...
Setting up python3-proton-vpn-network-manager (0.9.4) ...
Setting up proton-vpn-gnome-desktop (0.8.0) ...