Documentation updates for BIP 130

Author: sipa

doc/bips.md

@@ -18,3 +18,4 @@ BIPs that are implemented by Bitcoin Core (up-to-date up to **v0.12.0**):
 * [`BIP 66`](https://github.com/bitcoin/bips/blob/master/bip-0066.mediawiki): The strict DER rules and associated version 3 blocks have been implemented since **v0.10.0** ([PR #5713](https://github.com/bitcoin/bitcoin/pull/5713)).
 * [`BIP 70`](https://github.com/bitcoin/bips/blob/master/bip-0070.mediawiki) [`71`](https://github.com/bitcoin/bips/blob/master/bip-0071.mediawiki) [`72`](https://github.com/bitcoin/bips/blob/master/bip-0072.mediawiki): Payment Protocol support has been available in Bitcoin Core GUI since **v0.9.0** ([PR #5216](https://github.com/bitcoin/bitcoin/pull/5216)).
 * [`BIP 111`](https://github.com/bitcoin/bips/blob/master/bip-0111.mediawiki): `NODE_BLOOM` service bit added, but only enforced for peer versions `>=70011` as of **v0.12.0** ([PR #6579](https://github.com/bitcoin/bitcoin/pull/6579)).
+* [`BIP 130`](https://github.com/bitcoin/bips/blob/master/bip-0130.mediawiki): direct headers announcement is negotiated with peer versions `>=70012` as of **v0.12.0** ([PR 6494](https://github.com/bitcoin/bitcoin/pull/6494)).

doc/release-notes.md

@@ -206,6 +206,15 @@ Libsecp256k1 has undergone very extensive testing and validation.
 
 A side effect of this change is that libconsensus no longer depends on OpenSSL.
 
+Direct headers announcement (BIP 130)
+-------------------------------------
+
+Between compatible peers, BIP 130 direct headers announcement is used. This
+means that blocks are advertized by announcing their headers directly, instead
+of just announcing the hash. In a reorganization, all new headers are sent,
+instead of just the new tip. This can often prevent an extra roundtrip before
+the actual block is downloaded.
+
 0.12.0 Change log
 =================