[0.13.0.x] Add notes about changes in mining (#2628)

* Add `Mining` section to `Notable changes`, mention P2SH and `script` in `getblocktemplate`

* Also mention `coinbase_payload`

Author: UdjinM6

doc/release-notes.md

@@ -110,6 +110,20 @@ update a masternode list with additional proof data.
 
 Read more: https://github.com/dashpay/dips/blob/master/dip-0004.md
 
+Mining
+------
+Please note that masternode payments in `getblocktemplate` rpc are now returned as an array and not as
+a single object anymore. Make sure to apply corresponding changes to your pool software.
+
+Also, deterministic masternodes can now set their payout address to a P2SH address. The most common use
+case for P2SH is multisig but script can be pretty much anything. If your pool software doesn't recognize
+P2SH addresses, the simplest way to fix it is to use `script` field which shows scriptPubKey for each
+entry of masternode payments array in `getblocktemplate`.
+
+And finally, after DIP0003 activation your pool software must be able to produce Coinbase Special
+Transaction https://github.com/dashpay/dips/blob/master/dip-0004.md#coinbase-special-transaction.
+Use `coinbase_payload` from `getblocktemplate` to get extra payload needed to construct this transaction.
+
 PrivateSend
 -----------
 With further refactoring of PrivateSend code it became possible to implement mixing in few parallel
@@ -198,6 +212,7 @@ There are a few changes in existing RPC interfaces in this release:
 - `masternode status` and `masternode list` show some DIP0003 related info now;
 - `previousbits` and `coinbase_payload` fields were added in `getblocktemplate`;
 - `getblocktemplate` now returns an array for masternode payments instead of a single object (miners and mining pools have to upgrade their software to support multiple masternode payees);
+- masternode and superblock payments in `getblocktemplate` show payee scriptPubKey in `script` field in addition to payee address in `payee`;
 - `getblockchaininfo` shows BIP9 deployment progress;
 - `help command subCommand` should give detailed help for subcommands e.g. `help protx list`;
 - `compressed` option in `masternode genkey`;