The Signaling section of the BIP still requires support for filter type 0x01, which has been removed from the BIP.
The change to remove filter type 0x01 is here: https://github.com/bitcoin/bips/commit/4a85759f0229450f4a63b9404dfe8e8c10bdc92e#diff-367f1ff45d7efb5c6774e4112cd17489
It appears at though this reference simply was missed in the change. @Roasbeef @aakselrod