Upgrade ISC dhcpd to 4.3.5 to address missing hostname workaround
ISC DHCP Server 4.3.0 introduced a bug which caused hostnames to go missing in pfSense 2.3.x. This was addressed through a workaround in pfSense 2.3.2 (see ticket #6589). The issue was subsequently fixed upstream. The fix is now available in ISC DHCP Server 4.3.5 which was released today.
The workaround commits referenced in ticket #6589 can now be reverted on any branches that integrate ISC dhcpd 4.3.5.
See this forum thread for background.