<div class="releasenotes">
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-h2(#main). development main (as of 2023-04-17)
+h2(#main). development main (as of 2023-04-18)
"previous: Upgrading to 2.6.1":#v2_6_1
+h3. UseAWSS3v2Driver option removed
+
+The old "v1" S3 driver for keepstore has been removed. The new "v2" implementation, which has been the default since Arvados 2.5.0, is always used. The @Volumes.*.DriverParameters.UseAWSS3v2Driver@ configuration key is no longer recognized. If your config file uses it, remove it to avoid warning messages at startup.
+
h2(#v2_6_1). v2.6.1 (2023-04-17)
"previous: Upgrading to 2.6.0":#v2_6_0
"previous: Upgrading to 2.5.0":#v2_5_0
+h3. WebDAV InternalURLs must be reachable from controller nodes
+
+Ensure your internal keep-web service addresses are listed in the @Services.WebDAV.InternalURLs@ section of your configuration file, and reachable from controller processes, as noted on the "updated install page":{{site.baseurl}}/admin/config-urls.html.
+
h3. Slow migration on upgrade
Important! This upgrade includes a database schema update changing the integer id column in each table from 32-bit to 64-bit. Because it touches every row in the table, on moderate to large sized installations *this may be very slow* (on the order of hours). Plan for the arvados-api-server package upgrade to take longer than usual.