add note to Windows install, update JMQT guide

docs/INSTALL.md

@@ -170,6 +170,7 @@ rpc_cookie_file = /mnt/c/Users/Alice/AppData/Roaming/Bitcoin/.cookie
 2. Download and install [MobaXterm](https://mobaxterm.mobatek.net). This program needs to be running before you can start JoinMarket-Qt. It requires no additional configuration.
 3. Again in Ubuntu, type `DISPLAY=localhost:0.0` or add it to your `.bashrc` file so you don't need to type it every time you want to start JoinMarket-Qt.
 4. You can now start JoinMarket-Qt as described [here](JOINMARKET-QT-GUIDE.md).
+If you find that the program crashes with `qt.qpa.plugin: Could not load the Qt platform plugin`, you can add Qt5 dependencies with `sudo apt install qtbase5-dev` and try again.
 
 ### Alternative/custom installation:
 

docs/JOINMARKET-QT-GUIDE.md

@@ -4,17 +4,11 @@
 
 The gui can be run directly from Python script by doing `python joinmarket-qt.py` from within `scripts/`, or by running the executable file/binary (**[CLICK HERE](https://github.com/AdamISZ/joinmarket-clientserver/releases/)** to download the latest release).
 
-**LATEST VERSION of JoinMarket-Qt is GUI version 6**. You can check the version via `About` in the menu.
+**LATEST VERSION of JoinMarket-Qt is GUI version 9**. You can check the version via `About` in the menu.
 
 No other files / setup should be needed. You might need to `chmod 755` on Linux.
 
-The github commits to the main repo, above, are signed. For the executables in the release, there are .asc gpg signatures provided; please check them!
-
-My key (Adam Gibson, @AdamISZ on github, waxwing on reddit, btctalk, @waxwing__ on twitter): 
-
-    4668 9728 A9F6 4B39 1FA8  71B7 B3AE 09F1 E9A3 197A
-
-The gpg signature files for each binary should verify against the above key.
+The github commits to the main repo, above, are signed.
 
 **Contents**