updated to isc-dhcp-common_4.2.4-7ubuntu11_amd64 and isc-dhcp-client 4.2.4-7ubuntu11_amd64 solved this problem
updated to isc-dhcp- common_ 4.2.4-7ubuntu11 _amd64 and isc-dhcp-client 4.2.4-7ubuntu11 _amd64 solved this problem