diff --git a/srcpkgs/mono/patches/musl.patch b/srcpkgs/mono/patches/musl.patch
new file mode 100644
index 00000000000..0c523eb9c25
--- /dev/null
+++ b/srcpkgs/mono/patches/musl.patch
@@ -0,0 +1,11 @@
+--- mono/utils/mono-os-mutex.h	2019-09-25 17:24:27.868901488 +0200
++++ mono/utils/mono-os-mutex.h	2019-09-25 17:24:46.344659000 +0200
+@@ -57,7 +57,7 @@
+ 	if (G_UNLIKELY (res != 0))
+ 		g_error ("%s: pthread_mutexattr_settype failed with \"%s\" (%d)", __func__, g_strerror (res), res);
+ 
+-#if defined (PTHREAD_PRIO_INHERIT) && HAVE_DECL_PTHREAD_MUTEXATTR_SETPROTOCOL
++#if defined (PTHREAD_PRIO_INHERIT) && HAVE_DECL_PTHREAD_MUTEXATTR_SETPROTOCOL && defined(__GLIBC__)
+ 	/* use PTHREAD_PRIO_INHERIT if possible */
+ 	res = pthread_mutexattr_setprotocol (&attr, PTHREAD_PRIO_INHERIT);
+ 	if (G_UNLIKELY (res != 0 && res != ENOTSUP))
diff --git a/srcpkgs/mono/template b/srcpkgs/mono/template
index 2daef430f55..170438ae0dd 100644
--- a/srcpkgs/mono/template
+++ b/srcpkgs/mono/template
@@ -1,6 +1,6 @@
 # Template file for 'mono'
 pkgname=mono
-version=6.0.0.334
+version=6.4.0.198
 revision=1
 build_style=gnu-configure
 configure_args="--disable-system-aot"
@@ -13,7 +13,7 @@ maintainer="Helmut Pozimski <helmut@pozimski.eu>"
 license="MIT, BSD-3-Clause, GPL-2.0-or-later, LGPL-2.0-or-later, MPL-1.1"
 homepage="https://www.mono-project.com"
 distfiles="https://download.mono-project.com/sources/mono/${pkgname}-${version}.tar.xz"
-checksum=7b54157578f578487ee6c056c6f1802be8f567d9de39fcd66c0adb892936fe6b
+checksum=d00852822525e36f9f8b3e0f537d3a41c7a718cac22d06fc63ea64988877c2ea
 lib32disabled=yes
 python_version="3"