diff --git a/m4/windowmaker.m4 b/m4/windowmaker.m4
index c2492944..efd4fceb 100644
--- a/m4/windowmaker.m4
+++ b/m4/windowmaker.m4
@@ -13,8 +13,8 @@
 # GNU General Public License for more details.
 #
 # You should have received a copy of the GNU General Public License along
-# with this program; if not, write to the Free Software Foundation, Inc.,
-# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+# with this program; if not, see <https://www.gnu.org/licenses/>.
+
 
 
 dnl Tell m4 to not allow stuff starting with "WM_" in the generated file
diff --git a/m4/wm_attributes.m4 b/m4/wm_attributes.m4
index 3b4c8712..a15035a0 100644
--- a/m4/wm_attributes.m4
+++ b/m4/wm_attributes.m4
@@ -13,8 +13,8 @@
 # GNU General Public License for more details.
 #
 # You should have received a copy of the GNU General Public License along
-# with this program; if not, write to the Free Software Foundation, Inc.,
-# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+# with this program; if not, see <https://www.gnu.org/licenses/>.
+
 
 
 # WM_C_NORETURN
diff --git a/m4/wm_cflags_check.m4 b/m4/wm_cflags_check.m4
index b61b16d4..053c2d46 100644
--- a/m4/wm_cflags_check.m4
+++ b/m4/wm_cflags_check.m4
@@ -13,8 +13,8 @@
 # GNU General Public License for more details.
 #
 # You should have received a copy of the GNU General Public License along
-# with this program; if not, write to the Free Software Foundation, Inc.,
-# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+# with this program; if not, see <https://www.gnu.org/licenses/>.
+
 
 
 # WM_CFLAGS_CHECK_FIRST
diff --git a/m4/wm_imgfmt_check.m4 b/m4/wm_imgfmt_check.m4
index dce5b0d5..4f8609e4 100644
--- a/m4/wm_imgfmt_check.m4
+++ b/m4/wm_imgfmt_check.m4
@@ -13,8 +13,8 @@
 # GNU General Public License for more details.
 #
 # You should have received a copy of the GNU General Public License along
-# with this program; if not, write to the Free Software Foundation, Inc.,
-# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+# with this program; if not, see <https://www.gnu.org/licenses/>.
+
 
 
 # WM_IMGFMT_CHECK_GIF
diff --git a/m4/wm_libexif.m4 b/m4/wm_libexif.m4
index 1afd6cfb..e6952327 100644
--- a/m4/wm_libexif.m4
+++ b/m4/wm_libexif.m4
@@ -13,8 +13,8 @@
 # GNU General Public License for more details.
 #
 # You should have received a copy of the GNU General Public License along
-# with this program; if not, write to the Free Software Foundation, Inc.,
-# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+# with this program; if not, see <https://www.gnu.org/licenses/>.
+
 
 
 # WM_CHECK_LIBEXIF
diff --git a/m4/wm_libmath.m4 b/m4/wm_libmath.m4
index 5a8143c1..03603733 100644
--- a/m4/wm_libmath.m4
+++ b/m4/wm_libmath.m4
@@ -13,8 +13,8 @@
 # GNU General Public License for more details.
 #
 # You should have received a copy of the GNU General Public License along
-# with this program; if not, write to the Free Software Foundation, Inc.,
-# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+# with this program; if not, see <https://www.gnu.org/licenses/>.
+
 
 
 # WM_CHECK_LIBM
diff --git a/m4/wm_library_constructors.m4 b/m4/wm_library_constructors.m4
index 35250827..88771bac 100644
--- a/m4/wm_library_constructors.m4
+++ b/m4/wm_library_constructors.m4
@@ -13,8 +13,8 @@
 # GNU General Public License for more details.
 #
 # You should have received a copy of the GNU General Public License along
-# with this program; if not, write to the Free Software Foundation, Inc.,
-# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+# with this program; if not, see <https://www.gnu.org/licenses/>.
+
 
 
 # WM_LIBRARY_CONSTRUCTORS
diff --git a/m4/wm_prog_cc_c11.m4 b/m4/wm_prog_cc_c11.m4
index a841e6ea..2f51243d 100644
--- a/m4/wm_prog_cc_c11.m4
+++ b/m4/wm_prog_cc_c11.m4
@@ -13,8 +13,8 @@
 # GNU General Public License for more details.
 #
 # You should have received a copy of the GNU General Public License along
-# with this program; if not, write to the Free Software Foundation, Inc.,
-# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+# with this program; if not, see <https://www.gnu.org/licenses/>.
+
 
 
 # WM_PROG_CC_C11
diff --git a/m4/wm_xext_check.m4 b/m4/wm_xext_check.m4
index d482bdd5..a4c28a92 100644
--- a/m4/wm_xext_check.m4
+++ b/m4/wm_xext_check.m4
@@ -13,8 +13,8 @@
 # GNU General Public License for more details.
 #
 # You should have received a copy of the GNU General Public License along
-# with this program; if not, write to the Free Software Foundation, Inc.,
-# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+# with this program; if not, see <https://www.gnu.org/licenses/>.
+
 
 # WM_XEXT_CHECK_XRES
 # --------------------