Not sure if you want to stay compatible with IE11 (I think a few people still use it). Here are a couple issues with Contacts in SM 16.0.6345:
First, it seems like it takes a long time to open the pop out window. Just go to Contacts and click New. It takes 3-4 seconds to fill in the window. It's faster with Chrome, but there's still a delay.
Second, when you edit a contact and click any of the buttons at the top (Save, Cancel, Delete), IE pops up an annoying window asking if you want to leave this page.