I have two My Cloud devices The first has the software version 04.05.00-342 the second 2.41.116 Upgrade to OS5 is only possible on the second Cloud I understand that the first Cloud will not get the update to OS5?
So, after April 15, 2022, will I be able to log into the device with OS3 (v04.05.00-342) remotely via the website and the application on the phone or will I lose remote access and stay only on the local network?
You will lose website and phone access.
You will still have the ability to have VPN and other means of non-WD internet access. . .
. . .but bottom lines:
OS/3 devices should be OFF THE INTERNET today.
OS/5 - - - - Only slightly better. Frankly. . . .MyCloud Gen 2 is not really sufficient to effectively run OS/5. Too slow. Too little RAM.
Best path (Hate to break it to you): New hardware . . .currently recommend something running DSM software (hint: not WD)( Google NAS DSM)