hi
In the latest version it is no longer possible to have HTML in an attribute of the participants. Is this deliberate? Does anyone have a workaround? 
Kind regards

Never thought of entering HTML code into an participant attribute field.
My guess would be that it never was intended to allow HTML code inside an attribute field, but it just worked over the years.

I recommend to open a bugticket to find out and find other users with the same usercase. Please post the ticket id / link to the bugticket here.

bugs.limesurvey.org/

Link to bug-ticket: bugs.limesurvey.org/view.php?id=17840

The ONLY way to have html previously is to import CSV file by superadmin.
But if this superadmin edit token : it's remove html code

See github.com/LimeSurvey/LimeSurvey/pull/1666

I use myself html tag in token attribute, but since sometimes it disappear : the feature was worst than the issue.