diff -pruN 1:2.9.4-2/debian/changelog 1:2.9.4-2ubuntu2/debian/changelog
--- 1:2.9.4-2/debian/changelog	2025-04-13 22:10:01.000000000 +0000
+++ 1:2.9.4-2ubuntu2/debian/changelog	2025-08-07 06:19:05.000000000 +0000
@@ -1,3 +1,17 @@
+linuxcnc (1:2.9.4-2ubuntu2) questing; urgency=medium
+
+  * No-change rebuild for boost 1.88.
+
+ -- Matthias Klose <doko@ubuntu.com>  Thu, 07 Aug 2025 08:19:05 +0200
+
+linuxcnc (1:2.9.4-2ubuntu1) questing; urgency=medium
+
+  * Merge with Debian unstable (LP: #2104237).
+    Remaining changes:
+    - d/patches: Remove upstream definition of _FORTIFY_SOURCE (LP #2104012)
+
+ -- Florent 'Skia' Jacquet <florent.jacquet@canonical.com>  Thu, 19 Jun 2025 11:51:20 +0200
+
 linuxcnc (1:2.9.4-2) unstable; urgency=medium
 
   * Team upload.
@@ -11,6 +25,12 @@ linuxcnc (1:2.9.4-2) unstable; urgency=m
 
  -- Steffen Moeller <moeller@debian.org>  Mon, 14 Apr 2025 00:10:01 +0200
 
+linuxcnc (1:2.9.4-1ubuntu1) plucky; urgency=medium
+
+  * d/patches: Remove upstream definition of _FORTIFY_SOURCE (LP: #2104012)
+
+ -- Pushkar Kulkarni <pushkar.kulkarni@canonical.com>  Mon, 24 Mar 2025 19:18:59 +0530
+
 linuxcnc (1:2.9.4-1) unstable; urgency=medium
 
   * Team upload.
diff -pruN 1:2.9.4-2/debian/control 1:2.9.4-2ubuntu2/debian/control
--- 1:2.9.4-2/debian/control	2025-04-13 22:10:01.000000000 +0000
+++ 1:2.9.4-2ubuntu2/debian/control	2025-06-19 09:51:20.000000000 +0000
@@ -1,7 +1,8 @@
 Source: linuxcnc
 Section: misc
 Priority: optional
-Maintainer: LinuxCNC Developers <emc-developers@lists.sourceforge.net>
+Maintainer: Ubuntu Developers <ubuntu-devel-discuss@lists.ubuntu.com>
+XSBC-Original-Maintainer: LinuxCNC Developers <emc-developers@lists.sourceforge.net>
 Uploaders:
     Jeff Epler <jepler@gmail.com>,
     Sebastian Kuzminsky <seb@highlab.com>,
diff -pruN 1:2.9.4-2/debian/patches/remove_FORTIFY_SOURCE_redefinition.patch 1:2.9.4-2ubuntu2/debian/patches/remove_FORTIFY_SOURCE_redefinition.patch
--- 1:2.9.4-2/debian/patches/remove_FORTIFY_SOURCE_redefinition.patch	1970-01-01 00:00:00.000000000 +0000
+++ 1:2.9.4-2ubuntu2/debian/patches/remove_FORTIFY_SOURCE_redefinition.patch	2025-06-19 09:51:20.000000000 +0000
@@ -0,0 +1,21 @@
+Description: Remove redefinition of _FORTIFY_SOURCE
+  Starting Ubuntu 24.04, dpkg-buildflags passes _FORTIFY_SOURCE=3 by default.
+  On Debian, dpkg-buildflags passes _FORTIFY_SOURCE=2. Use of _FORTIFY_SOURCE=2
+  in the Makefile causes redefinition errors on Ubuntu. This patch enforces
+  depending on dpkg-buildflags for the _FORTIFY_SOURCE value.
+Author: Pushkar Kulkarni <pushkar.kulkarni@canonical.com>
+Bug-Ubuntu: https://bugs.launchpad.net/ubuntu/+source/linuxcnc/+bug/2104012
+Forwarded: https://github.com/LinuxCNC/linuxcnc/pull/3384
+Last-Update: 2025-03-24
+---
+--- a/src/Makefile
++++ b/src/Makefile
+@@ -252,7 +252,7 @@
+ # Compilation options.	Perhaps some of these should come from Makefile.inc? (CXXFLAGS now does)
+ INTEGER_OVERFLOW_FLAGS := -fwrapv
+ OPT := -Os $(INTEGER_OVERFLOW_FLAGS)
+-DEBUG := $(DEBUG) -g -Wall -D_FORTIFY_SOURCE=2
++DEBUG := $(DEBUG) -g -Wall
+ CFLAGS := $(INCLUDE) $(OPT) $(DEBUG) $(EXTRA_DEBUG) -DULAPI -std=gnu11 -Werror=implicit-function-declaration $(CFLAGS) $(CPPFLAGS)
+ CXXFLAGS := $(INCLUDE) $(EXTRA_DEBUG) -DULAPI $(DEBUG) $(OPT) -Werror=overloaded-virtual $(CXXFLAGS) $(CPPFLAGS)
+ CXXFLAGS += -std=gnu++17
diff -pruN 1:2.9.4-2/debian/patches/series 1:2.9.4-2ubuntu2/debian/patches/series
--- 1:2.9.4-2/debian/patches/series	1970-01-01 00:00:00.000000000 +0000
+++ 1:2.9.4-2ubuntu2/debian/patches/series	2025-06-19 09:51:20.000000000 +0000
@@ -0,0 +1 @@
+remove_FORTIFY_SOURCE_redefinition.patch