diff -Nru jansson-2.13.1/debian/changelog jansson-2.13.1/debian/changelog
--- jansson-2.13.1/debian/changelog	2020-06-28 12:46:50.000000000 +0000
+++ jansson-2.13.1/debian/changelog	2020-09-29 13:16:00.000000000 +0000
@@ -1,3 +1,11 @@
+jansson (2.13.1-1ubuntu1) groovy; urgency=medium
+
+  * debian/patches/git_new_sphinx.patch:
+    - backport an upstream change to fix the build with sphinx3
+      (Closes: #963640)
+
+ -- Sebastien Bacher <seb128@debian.org>  Tue, 29 Sep 2020 15:16:23 +0200
+
 jansson (2.13.1-1) unstable; urgency=medium
 
   * New upstream release (Closes: #963842)
diff -Nru jansson-2.13.1/debian/patches/git_new_sphinx.patch jansson-2.13.1/debian/patches/git_new_sphinx.patch
--- jansson-2.13.1/debian/patches/git_new_sphinx.patch	1970-01-01 00:00:00.000000000 +0000
+++ jansson-2.13.1/debian/patches/git_new_sphinx.patch	2020-09-28 10:44:49.000000000 +0000
@@ -0,0 +1,66 @@
+From 798d40c3f3e0700501de1588274b69e2b128ad7c Mon Sep 17 00:00:00 2001
+From: Pierce Lopez <pierce.lopez@gmail.com>
+Date: Fri, 7 Aug 2020 01:54:45 -0400
+Subject: [PATCH] doc: convert refcounting directive to a class
+
+Directive functions are no longer supported in Sphinx-3.0
+but directive classes have been supported since early 1.x
+---
+ doc/ext/refcounting.py | 31 ++++++++++++++++++++-----------
+ 1 file changed, 20 insertions(+), 11 deletions(-)
+
+diff --git a/doc/ext/refcounting.py b/doc/ext/refcounting.py
+index bba26849..e72c481c 100644
+--- a/doc/ext/refcounting.py
++++ b/doc/ext/refcounting.py
+@@ -24,8 +24,8 @@
+ """
+ 
+ from docutils import nodes
++from docutils.parsers.rst import Directive
+ 
+-class refcounting(nodes.emphasis): pass
+ 
+ def visit(self, node):
+     self.visit_emphasis(node)
+@@ -40,16 +40,25 @@ def html_depart(self, node):
+     self.body.append('</em>')
+ 
+ 
+-def refcounting_directive(name, arguments, options, content, lineno,
+-                   content_offset, block_text, state, state_machine):
+-    if arguments[0] == 'borrow':
+-        text = 'Return value: Borrowed reference.'
+-    elif arguments[0] == 'new':
+-        text = 'Return value: New reference.'
+-    else:
+-        raise Error('Valid arguments: new, borrow')
++class refcounting(nodes.emphasis):
++    pass
++
++class refcounting_directive(Directive):
++    has_content = False
++    required_arguments = 1
++    optional_arguments = 0
++    final_argument_whitespace = False
++
++    def run(self):
++        if self.arguments[0] == 'borrow':
++            text = 'Return value: Borrowed reference.'
++        elif self.arguments[0] == 'new':
++            text = 'Return value: New reference.'
++        else:
++            raise Error('Valid arguments: new, borrow')
++
++        return [refcounting(text, text)]
+ 
+-    return [refcounting(text, text)]
+ 
+ def setup(app):
+     app.add_node(refcounting,
+@@ -57,4 +66,4 @@ def setup(app):
+                  latex=(visit, depart),
+                  text=(visit, depart),
+                  man=(visit, depart))
+-    app.add_directive('refcounting', refcounting_directive, 0, (1, 0, 0))
++    app.add_directive('refcounting', refcounting_directive)
diff -Nru jansson-2.13.1/debian/patches/series jansson-2.13.1/debian/patches/series
--- jansson-2.13.1/debian/patches/series	1970-01-01 00:00:00.000000000 +0000
+++ jansson-2.13.1/debian/patches/series	2020-09-28 10:44:49.000000000 +0000
@@ -0,0 +1 @@
+git_new_sphinx.patch