diff --git a/.github/workflows/upload-to-pip.yml.yml b/.github/workflows/upload-to-pip.yml.yml
index 4425b85..1e0410c 100644
--- a/.github/workflows/upload-to-pip.yml.yml
+++ b/.github/workflows/upload-to-pip.yml.yml
@@ -1,8 +1,11 @@
 name: Upload to PIP
 
 on:
-  release: 
-    types: [created]
+  # Trigger the workflow on push or pull request,
+  # but only for the main branch
+  push:
+    branches:
+      - master
   workflow_dispatch:
 
 jobs:
diff --git a/requirements.txt b/requirements.txt
index 61b8b6b..2f36458 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,4 +1,4 @@
-pyyaml[yaml]
+PyYAML>=5.1
 sqlalchemy
 requests
 bs4
diff --git a/setup.py b/setup.py
index 0a4be28..913e481 100644
--- a/setup.py
+++ b/setup.py
@@ -106,11 +106,11 @@ def run_tests(self):
     tests_require=['pytest'],
     include_package_data=True,
     install_requires=['sqlalchemy', 'requests', 'numpy', 'pandas', 'numexpr', 'geopy', 'Flask-SQLAlchemy',
-                      'Flask', 'Flask-Caching', 'jinja2', 'pyyaml', 'records', 'psycopg2', 'click',
+                      'Flask', 'Flask-Caching', 'jinja2', 'PyYAML==5.4.1', 'records', 'psycopg2', 'click',
                       'Flask-GoogleMaps==0.2.4', 'owlready2', 'pint', 'Werkzeug'
                       ],
     cmdclass={'test': PyTest, 'install': CustomInstall},
-    python_requires='>=3.3',
+    python_requires='>=3.6',
     packages=find_packages(exclude=["tests.*", "tests"]),
     author_email='argysamo@gmail.com',
     package_data={