Sensitivity Labels and DLP

Hi,

I've implemented Sensitivity Labels. Our Infrastructure is on Premises Exchange 2016.

Sensitivity Labels are working correctly, however some of our Outlook version 2302 (Build 16130.20766) clients show the Sensitivity Labels in the ribbon with the shield colour and some of our clients don't show the shield with the colour. For example, Public shows a green shield for some clients and doesn't show a shield for other clients. Additionally, the drop down list on the right of the subject showing the label is absent for the clients where the shield colour is absent. There is no difference between the Office build or label deployment for the client and user. 

Secondly, is is possible to use the sensitivity labels in conjunction with Purview DLP with On Premises Exchange? I'd like to be able to apply DLP rules based on recipients with DLP rules, but it appears that this will not work with On Premises Exchange.

Thanks,

Ben