Are you trying to modify identity attribute in target application as based on behaviour your target application api is expecting every attribute value along with changes attribute value.
Please check with application team and modify you api request envelop before sending the request using before rule.
I’m just trying to modify one Identity attribute directly on the Identity. It seems like it is expecting that I also supply ALL OTHER Identity attributes, or else it will wipe them out.
I have replicate your use case. I just updated display name and it is updated but it wiped out first name, last name and email attributes. However manager attribute is not wiped out.
It looks like you need to do a GET first to get all the attributes and than perform the PUT with all attributes including the ones not changed and excluding the read-only attributes.
There is not a lot of documentation on the IIQ SCIM API
There might be a way to create a new Workflow (to update a particular attribute) and call that custom Workflow via the API.
But I would only go that route if it is focussed on 1 particular attribute/use-case on a regular basis (Like enable/disable based on an external event or alike).
If it is not something custom solution, I would suggest you to use batch requests to update identity data for bulk users. In my experience, we didn’t use any API in IIQ, we used OOTB solutions and custom solutions inside IIQ.