diff -pruN 2018.12.R1-1/debian/changelog 2018.12.R1-1.1/debian/changelog
--- 2018.12.R1-1/debian/changelog	2019-12-23 07:42:25.000000000 +0000
+++ 2018.12.R1-1.1/debian/changelog	2025-10-18 16:42:25.000000000 +0000
@@ -1,3 +1,10 @@
+libbtbb (2018.12.R1-1.1) unstable; urgency=medium
+
+  * Non-maintainer upload.
+  * add cmake4.patch (Closes: #1113123)
+
+ -- Thorsten Alteholz <debian@alteholz.de>  Sat, 18 Oct 2025 18:42:25 +0200
+
 libbtbb (2018.12.R1-1) unstable; urgency=medium
 
   * New upstream release (no changes, but updated version number)
diff -pruN 2018.12.R1-1/debian/patches/cmake4.patch 2018.12.R1-1.1/debian/patches/cmake4.patch
--- 2018.12.R1-1/debian/patches/cmake4.patch	1970-01-01 00:00:00.000000000 +0000
+++ 2018.12.R1-1.1/debian/patches/cmake4.patch	2025-10-18 16:42:25.000000000 +0000
@@ -0,0 +1,14 @@
+Description: increase minimal requested version of cmake (-> cmake4)
+Index: libbtbb/CMakeLists.txt
+===================================================================
+--- libbtbb.orig/CMakeLists.txt	2025-10-18 19:38:32.097582315 +0200
++++ libbtbb/CMakeLists.txt	2025-10-18 19:42:48.428030663 +0200
+@@ -20,7 +20,7 @@
+ #
+ #top level cmake project for libbtbb lib + tools
+ 
+-cmake_minimum_required(VERSION 2.8)
++cmake_minimum_required(VERSION 3.12)
+ project(libbtbb_all)
+ set(CMAKE_MODULE_PATH ${PROJECT_SOURCE_DIR}/cmake/modules)
+ 
diff -pruN 2018.12.R1-1/debian/patches/series 2018.12.R1-1.1/debian/patches/series
--- 2018.12.R1-1/debian/patches/series	2019-12-23 07:42:25.000000000 +0000
+++ 2018.12.R1-1.1/debian/patches/series	2025-10-18 16:42:25.000000000 +0000
@@ -1 +1,2 @@
 01_fix_python_install.patch
+cmake4.patch