diff --git a/CHANGES b/CHANGES
index 40a3966c0a..aabe5b1af7 100644
--- a/CHANGES
+++ b/CHANGES
@@ -3,7 +3,7 @@ Release Highlights
 
 Version 3.1.0 (unreleased)
 --------------------------
- *
+ * Qt5 versions less than 5.15 are no longer supported
 
 Version 3.0.1 (unreleased)
 --------------------------
diff --git a/CMakeLists.txt b/CMakeLists.txt
index b609cc23dd..901d585e7b 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -428,7 +428,7 @@ if(NOT DEFINED QT_VERSION_MAJOR)
     #
     find_package(
         QT
-        5.5
+        5.15
         NAMES
         Qt6
         Qt5
diff --git a/INSTALL.md b/INSTALL.md
index 7740f61191..d0ab131fc7 100644
--- a/INSTALL.md
+++ b/INSTALL.md
@@ -9,7 +9,8 @@ To build GammaRay you will need *at least*:
 
 - CMake 3.16.0
 - a C++ compiler with C++11 support
-- Qt 5.5 or higher, or Qt 6
+- Qt 5.15 or higher, or Qt 6
+  (GammaRay v3.0.1 was the last release to support Qt versions less than 5.15)
 
 Please be aware that GammaRay heavily relies on Qt private headers which can
 be changed at will by The Qt Company between releases and may need to be
diff --git a/docs/manual/gammaray-install.qdoc b/docs/manual/gammaray-install.qdoc
index 8eb0b0659b..0402e06388 100644
--- a/docs/manual/gammaray-install.qdoc
+++ b/docs/manual/gammaray-install.qdoc
@@ -60,7 +60,7 @@
     You can obtain the source code of GammaRay on \l{https://github.com/KDAB/GammaRay}{Github}. To build it you need
     the following requirements:
     \list
-        \li Qt 5.5 or newer
+        \li Qt 5.15 or newer
         \li CMake 3.4 or newer
         \li a C++11 compatible compiler
     \endlist
@@ -158,6 +158,6 @@
         export PATH=<toolchain>:$PATH
 
         cd <builddir>
-        cmake -DCMAKE_TOOLCHAIN_FILE=<srcdir>/cmake/Toolchain-RPI.cmake  -DCMAKE_PREFIX_PATH=$SYSROOT/usr/local/Qt-5.5.1 -DCMAKE_INSTALL_PREFIX=$SYSROOT/usr/ -DGAMMARAY_BUILD_UI=OFF
+        cmake -DCMAKE_TOOLCHAIN_FILE=<srcdir>/cmake/Toolchain-RPI.cmake  -DCMAKE_PREFIX_PATH=$SYSROOT/usr/local/Qt-5.15.1 -DCMAKE_INSTALL_PREFIX=$SYSROOT/usr/ -DGAMMARAY_BUILD_UI=OFF
     \endcode
 */