Hello,
Yes, wallets 5.x will work forever exactly as it works now, but it will not be updated any more and will gradually become obsolete.
And it will be up to you to update to wallets6 when you choose to do so.
Since you will have to make some small changes in your code: You can install wallets6 on a dev/integration machine and modify your code there, then deploy to live when you decide to upgrade to wallets6.
with regards