This statement is from the release notes - section People:
Contacts saved on the device are no longer synced to all accounts, only the account you have chosen
Means, that each contact has at least one source: phone, and maybe more synced accounts like Google or NextCloud in parallel and these can only be edited for one part/source and no merging possible.
Some question arise with that:
how can I manage for each contact, or better for all contacts at once, this sync-accounts? Like to have all contacts synced to various accounts in parallel: add a sync-account to all contacts at once.
how can I enrich/combine the data from different accounts into one dataset for each contact? If my local phone-part of a contact does not have the phone number included, WhatsApp will not know this contact at all
Moreover: during the adding of a new contact on the phone you can only chose one (1) sync-account!
This breaks the whole concept of syncing as backup to different accounts: either you have the contact on the phone and available for WhatsApp but not synced to Google - or vice-verse: having it synced to Google and not even available for the Phonebook - not to mention WhatsApp (were this contact is also not available).
I haven’t even found a way to sync any of the contacts I have on my device to Google. (I added my Google account only after I upgraded to 4, all contacts are stored locally.)
What happened on a so-called 2-way-sync was that the 1 test contact i had added to Google contacts before got synced to my device. That’s all. I see no way in the UI to upload/backup/save/sync whatever you call it the old, locally stored contacts to Google. Thats an absurd situation.
In your jolla account (online) you can choose to opt-in to the Early Access releases. I have a second SFOS phone that I will update at some point and report back. I did not see anything mentioned about this issue in the release notes.
I just updated one XA2 Plus to 4.1 and you still can’t change where the contact is stored. Phone or Online. You can link contacts but you can not merge and decide where it should reside.
This means that you could have some contacts on your phone with details that are not synced online to other phones or devices. Could be a feature or an annoyance.