DHCP required forces a client to initiate a DHCP request after it joins the WiFi because any traffic sent from any other IP will be dropped.DHCP not required means clients can use static IP if they want to, or some dumb clients will not renew DHCP on...

This thread looks like it is partly a duplicate of your other question at https://community.cisco.com/t5/switches-small-business/cant-ping-from-another-vlan/td-p/5156754 where I have explained routing between VLANs for you.

You need a router to route traffic between VLANs.According to https://www.cisco.com/c/en/us/products/collateral/switches/small-business-smart-switches/data_sheet_c78-610061.html "Features include:◦    Static routing/Layer 3 switching between VLANs: T...

No release date for 17.15.1 has been announced but I would expect it to be sometime in the September-October timeframe. Joining the beta and testing the features you're interested in will give you the chance to report any bugs (very likely for a new ...