All is working for me on 4.15.0-24-generic #26~16.04.1-Ubuntu.
bcmwl-kernel-source/xenial-proposed,now 6.30.223.271+bdcom-0ubuntu1~1.3 amd64 [installed]
kernel: wlan0: Broadcom BCM4331 802.11 Hybrid Wireless Controller 6.30.223.271 (r587334)
All is working for me on 4.15.0-24-generic #26~16.04.1-Ubuntu.
bcmwl-kernel- source/ xenial- proposed, now 6.30.223. 271+bdcom- 0ubuntu1~ 1.3 amd64 [installed]
kernel: wlan0: Broadcom BCM4331 802.11 Hybrid Wireless Controller 6.30.223.271 (r587334)