diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index b98277fd..649fa1de 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -1,16 +1,16 @@
 repos:
   - repo: https://github.com/pre-commit/pre-commit-hooks
-    rev: v2.3.0
+    rev: v4.0.1
     hooks:
       - id: check-yaml
       - id: end-of-file-fixer
       - id: trailing-whitespace
   - repo: https://github.com/psf/black
-    rev: 19.3b0
+    rev: 21.7b0
     hooks:
       - id: black
   - repo: https://github.com/kynan/nbstripout
-    rev: master
+    rev: 0.5.0
     hooks:
       - id: nbstripout
         files: ".ipynb"
diff --git a/CONTRIBUTORS b/CONTRIBUTORS
index 2d4b231c..1afa2942 100644
--- a/CONTRIBUTORS
+++ b/CONTRIBUTORS
@@ -12,4 +12,3 @@ Many thanks to the following users who have contributed to improving the content
 @RyPeck
 @zmilicc
 @MridulS
-