re : But mozilla does not support a download link of a (dutch) version thunderbird 52.9.1?

http://ftp.mozilla.org/pub/thunderbird/releases/52.9.1/win32/nl/

Version 60 release notes: https://www.thunderbird.net/en-US/thunderbird/60.0/releasenotes/ Thunderbird version 60.0 is only offered as direct download from thunderbird.net and not as upgrade from Thunderbird version 52 or earlier. A future version 60.1 will provide updates from earlier versions. If you have installed Lightning, Thunderbird's Calendar add-on, it will automatically be updated to match the new version of Thunderbird.

IMPORTANT: Add-ons not marked as compatible with Thunderbird 60 by their authors will be disabled (this can be reverted via preference extensions.strictCompatibility)

Hansb said

But mozilla does not support a download link of a (dutch) version thunderbird 52.9.1?

The Thunderbird community that makes Thunderbird does have a Dutch locale available among many other languages as it is listed on the Systems & Languages link on https://www.thunderbird.net

On https://www.thunderbird.net/thunderbird/all/ scroll down a little to Dutch locale of the current Tb 60.0 Release

Thanks Toad Hall for your link to version 52.9.1 (dutch) Your explanation tells:

"A future version 60.1 will provide updates from earlier versions."

Does this means 52.9.1 will be upgraded automatically to versions 60.1 and later?

Hansb said

Thanks Toad Hall for your link to version 52.9.1 (dutch) Your explanation tells: "A future version 60.1 will provide updates from earlier versions." Does this means 52.9.1 will be upgraded automatically to versions 60.1 and later?

Yes, the delay is to limit those on V60 until the folk in charge are sure there are no major flaws that slipped through testing.

Hallo daar.

Ik heb jouw probleem gelezen. Is dit nu opgelost? Anders zou ik je graag verder willen helpen.

Heb je verder nog vragen mail dan gerust.

We staan klaar. Blijf het goede spul gebruiken.

Groeten