dansoftware wrote:

No, except ownCloud.

But they do not support it either, right?

Here is how the problem is solved in another WebDAV software:
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No, except ownCloud.

Do you have any reference for use of lastmodified?

Well, it seems to me that it is good idea to add an option to WinSCP to change its behavior between getlastmodified and lastmodified.

I do not know any WebDAV server that does support lastmodified either. On the contrary there is a server that does support getlastmodified. That's why WinSCP uses it.

Once there's any server that correctly supports lastmodified, I'm happy to change WinSCP behavior.

You are right. This is my post on ownCloud repository. Nor lastmodified nor getlastmodified does not work with ownCloud actually. It seems that there is a bug in ownCloud around PROPPATCH+lastmodified. It responses HTTP/1.1 200 OK but mtime of a file is not changed actually. I do not use any other WebDAV server. So I don't know how lastmodified property is well supported.

Well, I'm aware of that, as you probably know from the discussions on ownCloud repository.

Do you know of any server that actually supports setting lastmodified?
It looks like ownCloud still does not support it, as per your own post at:
https://github.com/owncloud/core/issues/33502#issuecomment-520416410
Or does it?

Hello.

WinSCP uses property getlastmodified with PROPPATCH method to modify mtime of a file on a WebDAV storage. It is incorrect. getlastmodified is read only and should be used with PROPFIND only. lastmodified property should be used with PROPPATCH instead: https://github.com/owncloud/core/issues/19737 Please, fix the problem.