diff -Nru mongo-c-driver-1.16.1/debian/changelog mongo-c-driver-1.16.1/debian/changelog
--- mongo-c-driver-1.16.1/debian/changelog	2020-02-06 19:30:48.000000000 +0000
+++ mongo-c-driver-1.16.1/debian/changelog	2020-06-07 19:41:40.000000000 +0000
@@ -1,3 +1,10 @@
+mongo-c-driver (1.16.1-1+rpi1) bullseye-staging; urgency=medium
+
+  * Add upstream patch to fix FTBFS with sphinx 2.4
+    (Closes: 955114)
+
+ -- Peter Michael Green <plugwash@raspbian.org>  Sun, 07 Jun 2020 19:41:40 +0000
+
 mongo-c-driver (1.16.1-1) unstable; urgency=medium
 
   * New upstream release
diff -Nru mongo-c-driver-1.16.1/debian/patches/fix-sphinx-2.4.patch mongo-c-driver-1.16.1/debian/patches/fix-sphinx-2.4.patch
--- mongo-c-driver-1.16.1/debian/patches/fix-sphinx-2.4.patch	1970-01-01 00:00:00.000000000 +0000
+++ mongo-c-driver-1.16.1/debian/patches/fix-sphinx-2.4.patch	2020-06-07 19:40:47.000000000 +0000
@@ -0,0 +1,28 @@
+commit 214c433997ffbed6f36e2ba46218c5beb30a6107
+Author: Roberto C. Sánchez <roberto@connexer.com>
+Date:   Mon Mar 30 19:37:03 2020 -0400
+
+    CDRIVER-3594 build Sphinx docs without parallelism
+
+diff --git a/build/cmake/SphinxBuild.cmake b/build/cmake/SphinxBuild.cmake
+index a7f49d79b..f90308486 100644
+--- a/build/cmake/SphinxBuild.cmake
++++ b/build/cmake/SphinxBuild.cmake
+@@ -40,7 +40,7 @@ function (sphinx_build_html target_name doc_dir)
+       ${CMAKE_COMMAND} -E env
+       "PYTHONDONTWRITEBYTECODE=1"
+       ${SPHINX_EXECUTABLE}
+-         -j ${NPROCS} -qEW -b html
++         -qEW -b html
+          -c "${CMAKE_CURRENT_SOURCE_DIR}"
+          "${CMAKE_CURRENT_SOURCE_DIR}"
+          "${SPHINX_HTML_DIR}"
+@@ -133,7 +133,7 @@ function (sphinx_build_man target_name)
+       ${CMAKE_COMMAND} -E env
+       "PYTHONDONTWRITEBYTECODE=1"
+       ${SPHINX_EXECUTABLE}
+-         -j ${NPROCS} -qEW -b man
++         -qEW -b man
+          -c "${CMAKE_CURRENT_SOURCE_DIR}"
+          "${CMAKE_CURRENT_SOURCE_DIR}"
+          "${SPHINX_MAN_DIR}"
diff -Nru mongo-c-driver-1.16.1/debian/patches/series mongo-c-driver-1.16.1/debian/patches/series
--- mongo-c-driver-1.16.1/debian/patches/series	1970-01-01 00:00:00.000000000 +0000
+++ mongo-c-driver-1.16.1/debian/patches/series	2020-06-07 19:41:15.000000000 +0000
@@ -0,0 +1 @@
+fix-sphinx-2.4.patch