diff --git a/pkgs/applications/version-management/monotone/default.nix b/pkgs/applications/version-management/monotone/default.nix
index 48af459260d..6ea66b296d7 100644
--- a/pkgs/applications/version-management/monotone/default.nix
+++ b/pkgs/applications/version-management/monotone/default.nix
@@ -30,7 +30,10 @@ stdenv.mkDerivation rec {
     hash = "sha256:1hfy8vaap3184cd7h3qhz0da7c992idkc6q2nz9frhma45c5vgmd";
   };
 
-  patches = [ ./monotone-1.1-Adapt-to-changes-in-pcre-8.42.patch ];
+  patches = [
+    ./monotone-1.1-Adapt-to-changes-in-pcre-8.42.patch
+    ./monotone-1.1-adapt-to-botan2.patch
+  ];
 
   postPatch = ''
     sed -e 's@/usr/bin/less@${less}/bin/less@' -i src/unix/terminal.cc
diff --git a/pkgs/applications/version-management/monotone/monotone-1.1-adapt-to-botan2.patch b/pkgs/applications/version-management/monotone/monotone-1.1-adapt-to-botan2.patch
new file mode 100644
index 00000000000..1df6a4717d5
--- /dev/null
+++ b/pkgs/applications/version-management/monotone/monotone-1.1-adapt-to-botan2.patch
@@ -0,0 +1,15 @@
+Botan2 has switched the parameter order in encryption descriptions
+
+--- monotone-upstream/src/botan_glue.hh 2021-08-17 19:06:32.736753732 +0200
++++ monotone-patched/src/botan_glue.hh  2021-08-17 19:07:44.437750535 +0200
+@@ -45,7 +45,9 @@
+ // In Botan revision d8021f3e (back when it still used monotone) the name
+ // of SHA-1 changed to SHA-160.
+ const static char * PBE_PKCS5_KEY_FORMAT =
+-#if BOTAN_VERSION_CODE >= BOTAN_VERSION_CODE_FOR(1,11,0)
++#if BOTAN_VERSION_CODE >= BOTAN_VERSION_CODE_FOR(2,0,0)
++  "PBE-PKCS5v20(TripleDES/CBC,SHA-160)";
++#elif BOTAN_VERSION_CODE >= BOTAN_VERSION_CODE_FOR(1,11,0)
+   "PBE-PKCS5v20(SHA-160,TripleDES/CBC)";
+ #else
+   "PBE-PKCS5v20(SHA-1,TripleDES/CBC)";