Nagvis fails with BI objects

Hello, I have CRE version 1.6.0p11 and I have created a map in Nagvis. When adding an object aggregation and selecting the backend_id = <site_bi> I get the following error:

image

The error message is very long, but among the most prominent messages I see this:

ERROR: Internal error: ‘dict’ object has no attribute ‘strip’ <p>An internal error occured while processing your request. You can report this issue to the Check_MK team to help fixing this issue.

You need to upgrade to p12 or newer.
This is from the change log.

[#10878] 1.6.0p12 2020-04-06 11:45:56 Bug fix Trivial change Compatible User interface Fix BI aggregation state export (Regression caused by #10879)

thank you @andreas-doehler for your answer, I will try to update as soon as possible.