diff --git a/dev-octave/quaternion/files/quaternion-2.4.0-build-against-octave-6.patch b/dev-octave/quaternion/files/quaternion-2.4.0-build-against-octave-6.patch
new file mode 100644
index 0000000000..756f872dc8
--- /dev/null
+++ b/dev-octave/quaternion/files/quaternion-2.4.0-build-against-octave-6.patch
@@ -0,0 +1,23 @@
+Description: Build against Octave 6.1
+ Replace deprecated methods is_numeric_type, is_real_type, and
+ is_bool_type by isnumeric, isreal, and islogical, respectively.
+Author: Rafael Laboissière <rafael@debian.org>
+Origin: other, https://hg.octave.org/mxe-octave/file/tip/src/of-quaternion-2-dev-fixes.patch
+Bug: https://savannah.gnu.org/bugs/?59163
+Bug-Debian: https://bugs.debian.org/976203
+Forwarded: not-needed
+Last-Update: 2020-12-01
+
+--- octave-quaternion-2.4.0.orig/src/is_real_array.cc
++++ octave-quaternion-2.4.0/src/is_real_array.cc
+@@ -46,8 +46,8 @@ Avoid nasty stuff like @code{true = isre
+         {
+             // args(i).ndims () should be always >= 2
+             if (args(i).ndims () < 2
+-                || ! ((args(i).is_numeric_type () && args(i).is_real_type ())
+-                      || args(i).is_bool_type ()))
++                || ! ((args(i).isnumeric () && args(i).isreal ())
++                      || args(i).islogical ()))
+             {
+                 retval = false;
+                 break;
diff --git a/dev-octave/quaternion/quaternion-2.4.0.ebuild b/dev-octave/quaternion/quaternion-2.4.0.ebuild
index d8ef1a0955..c84091f9d5 100644
--- a/dev-octave/quaternion/quaternion-2.4.0.ebuild
+++ b/dev-octave/quaternion/quaternion-2.4.0.ebuild
@@ -14,3 +14,5 @@ KEYWORDS="~amd64"
 
 DEPEND=">=sci-mathematics/octave-3.8.0"
 RDEPEND="${DEPEND}"
+
+PATCHES=( "${FILESDIR}/${P}-build-against-octave-6.patch" )