[xen staging] Update Xen version to 4.21.0-rc1

[patchbot@xxxxxxx]

commit d1478321eacbfca57c33dcc106984c7e63f9ad7e
Author:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
AuthorDate: Mon Oct 6 21:07:14 2025 +0100
Commit:     Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
CommitDate: Tue Oct 7 15:13:16 2025 +0100

    Update Xen version to 4.21.0-rc1
    
    Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
    Acked-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
    Release-Acked-By: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>
---
 README       | 10 +++++-----
 SUPPORT.md   |  2 +-
 xen/Makefile |  2 +-
 3 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/README b/README
index 9329f30e13..eaee78bd73 100644
--- a/README
+++ b/README
@@ -1,9 +1,9 @@
 ############################################################
-__  __                                _        _     _
-\ \/ /___ _ __        _   _ _ __  ___| |_ __ _| |__ | | ___
- \  // _ \ '_ \ _____| | | | '_ \/ __| __/ _` | '_ \| |/ _ \
- /  \  __/ | | |_____| |_| | | | \__ \ || (_| | |_) | |  __/
-/_/\_\___|_| |_|      \__,_|_| |_|___/\__\__,_|_.__/|_|\___|
+ __  __            _  _    ____  _
+ \ \/ /___ _ __   | || |  |___ \/ |   _ __ ___
+  \  // _ \ '_ \  | || |_   __) | |__| '__/ __|
+  /  \  __/ | | | |__   _| / __/| |__| | | (__
+ /_/\_\___|_| |_|    |_|(_)_____|_|  |_|  \___|
 
 ############################################################
 
diff --git a/SUPPORT.md b/SUPPORT.md
index eb44ee85fd..491f9ecd1b 100644
--- a/SUPPORT.md
+++ b/SUPPORT.md
@@ -9,7 +9,7 @@ for the definitions of the support status levels etc.
 
 # Release Support
 
-    Xen-Version: 4.21-unstable
+    Xen-Version: 4.21-rc
     Initial-Release: n/a
     Supported-Until: TBD
     Security-Support-Until: Unreleased - not yet security-supported
diff --git a/xen/Makefile b/xen/Makefile
index 49da79e10f..ba8c7147a2 100644
--- a/xen/Makefile
+++ b/xen/Makefile
@@ -6,7 +6,7 @@ this-makefile := $(call lastword,$(MAKEFILE_LIST))
 # All other places this is stored (eg. compile.h) should be autogenerated.
 export XEN_VERSION       = 4
 export XEN_SUBVERSION    = 21
-export XEN_EXTRAVERSION ?= -unstable$(XEN_VENDORVERSION)
+export XEN_EXTRAVERSION ?= .0-rc1$(XEN_VENDORVERSION)
 export XEN_FULLVERSION   = $(XEN_VERSION).$(XEN_SUBVERSION)$(XEN_EXTRAVERSION)
 -include xen-version
 
--
generated by git-patchbot for /home/xen/git/xen.git#staging