diff -Nar -u0 a/requirements/base.txt b/requirements/base.txt
--- a/requirements/base.txt	2021-06-09 14:25:03.000000000 +0000
+++ b/requirements/base.txt	2021-06-23 18:36:51.108332870 +0000
@@ -7 +6,0 @@
-contextvars
diff --git a/requirements/zeromq.txt b/requirements/zeromq.txt
--- a/requirements/zeromq.txt
+++ b/requirements/zeromq.txt
@@ -4,3 +4 @@
-pyzmq<=20.0.0 ; python_version < "3.6"
-pyzmq>=17.0.0,<22.0.0 ; python_version < "3.9"
-pyzmq>19.0.2,<22.0.0 ; python_version >= "3.9"
+pyzmq>=17.0.0