diff --git a/requirements/docs.txt b/requirements/docs.txt
index 2436f5af..aa5ca594 100644
--- a/requirements/docs.txt
+++ b/requirements/docs.txt
@@ -1,7 +1,6 @@
-docutils==0.16.0
+docutils>=0.16.0
 recommonmark
-sphinx==4.0.2
+sphinx>=4.0.2
 sphinx-book-theme
 sphinx-copybutton
 sphinx_markdown_tables
-sphinx_rtd_theme==0.5.2
diff --git a/requirements/nlp.txt b/requirements/nlp.txt
index 827bd512..dbdc7ad4 100644
--- a/requirements/nlp.txt
+++ b/requirements/nlp.txt
@@ -1,5 +1,3 @@
-
-http://ait-public.oss-cn-hangzhou-zmf.aliyuncs.com/jizhu/en_core_web_sm-2.3.1.tar.gz
 pai-easynlp
 rouge_score
 sofa>=1.0.5
diff --git a/requirements/tests.txt b/requirements/tests.txt
index e73858ca..5ec4df7e 100644
--- a/requirements/tests.txt
+++ b/requirements/tests.txt
@@ -1,5 +1,5 @@
 expecttest
 flake8
-isort==4.3.21
+isort>=4.3.21
 pre-commit
-yapf==0.30.0
+yapf==0.30.0 # use fix version to ensure consistent auto-styling