Problem database after update

After the update, the backup does not start, it shows this error, what should I do? Please help me, dear ones.

The database has version 11 but the largest supported version is 10. This is likely caused by upgrading to a newer version and then downgrading. If this is the case, there is likely a backup file of the previous database version in the folder

Welcome to the forum @student600

What does About → System info say for BaseVersionName and ServerVersionName?

What OS is this?

Do you recall what you updated to? The symptoms suggest 2.0.5.1 to 2.0.6.1, then 2.0.6.1 didn’t stick.

EDIT:

I suppose you could start looking into see what updates are installed. There’s an OS-dependent list at
Downgrading / reverting to a lower version

If you’re on Windows, you don’t have a service install if you just used the GUI installer from the .msi file.
If you’re on Linux, you would either install the package and let systemd start it, or start it at a user login.
It would be helpful to know how you start Duplicati and whether it runs as you or as some system user.

Here’s what it says about the system:
** APIVersion : 1*
** PasswordPlaceholder : ***********
** ServerVersion : 2.0.5.1*
** ServerVersionName : - 2.0.5.1_beta_2020-01-18*
** ServerVersionType : Beta*
** StartedBy : Tray icon*
** BaseVersionName : 2.0.5.1_beta_2020-01-18*
** DefaultUpdateChannel : Beta*
** DefaultUsageReportLevel : Information*
** ServerTime : 2021-06-15T13:11:11.2066205+03:00*
** OSType : Windows*

From which version I tried to update to which one it is difficult to say

Because you’re on the Beta channel (and also from the database version numbers which are given in the 2.0.6.1 release notice), and because your BaseVersionName is 2.0.5.1, there’s little chance you were on anything other than 2.0.5.1 before unless you were doing exotic things like changing your update channel.

Please look for folder C:\Users\<Duplicati user account>\AppData\Local\Duplicati\updates\
Possibly you will have to tell Explorer to View hidden items (otherwise AppData may not be shown to you)

Is there a 2.0.6.1 folder there? If so, try moving it to some other directory, then retrying the 2.0.6.1 update.
About → Check for updates now (below the line that probably says it’s running 2.0.5.1) is the way to start.

Download and install as usual, and you’ll probably see 2.0.6.1 show up where the previous one had been.
The Activate button is not reliable. If Duplicati just stops, you can start it again, e.g. using the desktop icon.

When up, see what version you’re on. It should be 2.0.6.1. If it works, then next is a folder comparison for possible changes between the working 2.0.6.1 and the bad one that you moved. Easy overview is to use right-click → Properties on the folders to compare sizes and counts. Maybe some changes can be found.

I stopped working and downloaded version 2.0.5. 114_canary_2021-03-10. msi, then reinstalled it and everything works, but still offers to upgrade to the latest version, I don’t want to use the developer versions, I need to get stable versions for updates, but how do I switch from the Canary channel to stable or something like that? There is nothing like this in the settings.

What is it offering? You’re already on latest Canary if you’re on 2.0.5.114. Sometimes old offerings hang around longer than you might like. If it’s offering 2.0.6.1, then you can take it, but I think it will leave you on Canary update channel unless you install 2.0.6.1 Beta from .msi, or change Settings. See details below.

You click Beta button as shown on your screenshot. See explanations there.

If you were going to download and install a .msi, and wanted something less potentially flaky (though often the fixes outweigh the new bugs), then 2.0.6.1 Beta would have been what to get. This will also set update channel to Beta (fresh installs set the channel to whatever channel they’re from), and save you the trouble.