doc: Clean out release notes after 0.17.0.1

Tree-SHA512: c04192e3b93537f4b37f5ea55fd455b26dd7d902da3b5f8b59ef6fa4590cf413b72fc11bba330a8fd7fa3938b09e6c1d35171806ab5ce85d6b99681953c291a5

doc/release-notes.md

@@ -1,8 +1,12 @@
-Bitcoin Core version 0.17.0.1 is now available from:
+(note: this is a temporary file, to be added-to by anybody, and moved to
+release-notes at release time)
 
-  <https://bitcoincore.org/bin/bitcoin-core-0.17.0.1/>
+Bitcoin Core version 0.17.x is now available from:
 
-This release provides a minor bug fix for 0.17.0.
+  <https://bitcoincore.org/bin/bitcoin-core-0.17.x/>
+
+This is a new major version release, including new features, various bugfixes
+and performance improvements, as well as updated translations.
 
 Please report bugs using the issue tracker at GitHub:
 
@@ -12,30 +16,72 @@ To receive security and update notifications, please subscribe to:
 
   <https://bitcoincore.org/en/list/announcements/join/>
 
-Notable changes
-===============
+How to Upgrade
+==============
+
+If you are running an older version, shut it down. Wait until it has completely
+shut down (which might take a few minutes for older versions), then run the
+installer (on Windows) or just copy over `/Applications/Bitcoin-Qt` (on Mac)
+or `bitcoind`/`bitcoin-qt` (on Linux).
+
+If your node has a txindex, the txindex db will be migrated the first time you run 0.17.0 or newer, which may take up to a few hours. Your node will not be functional until this migration completes.
+
+The first time you run version 0.15.0 or newer, your chainstate database will be converted to a
+new format, which will take anywhere from a few minutes to half an hour,
+depending on the speed of your machine.
+
+Note that the block database format also changed in version 0.8.0 and there is no
+automatic upgrade code from before version 0.8 to version 0.15.0. Upgrading
+directly from 0.7.x and earlier without redownloading the blockchain is not supported.
+However, as usual, old wallet versions are still supported.
+
+Downgrading warning
+-------------------
+
+The chainstate database for this release is not compatible with previous
+releases, so if you run 0.15 and then decide to switch back to any
+older version, you will need to run the old release with the `-reindex-chainstate`
+option to rebuild the chainstate data structures in the old format.
+
+If your node has pruning enabled, this will entail re-downloading and
+processing the entire blockchain.
 
-An issue was solved with OSX dmg generation, affecting macOS 10.12 to 10.14,
-which could cause Finder to crash on install.
+Compatibility
+==============
 
-There are no significant changes for other operating systems.
+Bitcoin Core is extensively tested on multiple operating systems using
+the Linux kernel, macOS 10.10+, and Windows 7 and newer (Windows XP is not supported).
 
-0.17.0.1 change log
-===================
+Bitcoin Core should also work on most other Unix-like systems but is not
+frequently tested on them.
 
-### Build system
-- #14416 `eb2cc84` Fix OSX dmg issue (10.12 to 10.14) (jonasschnelli)
+From 0.17.0 onwards macOS <10.10 is no longer supported. 0.17.0 is built using Qt 5.9.x, which doesn't
+support versions of macOS older than 10.10.
 
-### Documentation
-- #14509 `1b5af2c` [0.17] doc: use SegWit in getblocktemplate example (Sjors)
+Known issues
+============
+
+...
+
+Notable changes
+===============
+
+...
+
+0.17.x change log
+=================
+
+...
 
 Credits
 =======
 
 Thanks to everyone who directly contributed to this release:
 
-- Jonas Schnelli
-- Pieter Wuille
-- Sjors Provoost
-- Wladimir J. van der Laan
+...
+
+And to those that reported security issues:
+
+...
 
+As well as everyone that helped translating on [Transifex](https://www.transifex.com/projects/p/bitcoin/).