prepare release 4.2.1

RELEASE-NOTES

@@ -1,3 +1,30 @@
+# Release 4.2.1 - (March 24, 2022)
+ * Binaries:
+   - Windows: we are dropping support for Windows 7. (#7728)
+     Version 4.2.0 already unintentionally broke compatibility with
+     Win7 and there is no easy way to restore and maintain support.
+     Existing users can keep using version 4.1.5 for now, but should
+     consider upgrading or changing their OS.
+     Win8.1 still works but only Win10 is regularly tested.
+   - bump bundled Python version (win, mac, appimage) to 3.9.11,
+     (android) to 3.8.13 (1bb7ef92, #7721)
+     (note these include a fix to an openssl DOS-vector CVE-2022-0778)
+   - windows: bump pyinstaller to 4.10 and wine to 7.0 (#7721)
+ * Kivy GUI:
+   - fix "Child Pays For Parent" not working on Android (#7723)
+   - revert to defaulting the UI language to English (25fee6a6)
+ * Qt GUI:
+   - macOS: fix opening "Preferences" segfaulting for some (#7725)
+   - more resilient startup: better error-handling and fallback (#7447)
+ * Library:
+   - fix LN error/warning message-handling, and fix regression that
+     errors during channel-open were not properly shown in GUI (a92dede4)
+   - during LN chan open, do not backup wallet automatically (#7733)
+   - Imported wallets: fix delete_address rm-ing too many txs (#7587)
+   - fix potential deadlock in wallet.py (d3476b6b)
+ * fix the "--portable" flag for AppImage, and for pip installs (#7732)
+
+
 # Release 4.2.0 - (March 16, 2022)
  * The minimum python version was increased to 3.8 (#7661)
  * Lightning:

electrum/version.py

@@ -1,5 +1,5 @@
-ELECTRUM_VERSION = '4.2.0'     # version of the client package
-APK_VERSION = '4.2.0.0'        # read by buildozer.spec
+ELECTRUM_VERSION = '4.2.1'     # version of the client package
+APK_VERSION = '4.2.1.0'        # read by buildozer.spec
 
 PROTOCOL_VERSION = '1.4'     # protocol version requested