diff --git a/Dockerfile b/Dockerfile
index b47ac2b..b63df8b 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -90,11 +90,11 @@ RUN conda install -y \
     sync && \
     pip install \
         matplotlib \
-        mkl=2021.2 \
-        mkl-service=2.3 \
-        libxml2=2.9.8 \
-        libxslt=1.1.32 \
-        graphviz=2.40.1 \
+        mkl==2021.2 \
+        mkl-service==2.3 \
+        libxml2==2.9.8 \
+        libxslt==1.1.32 \
+        graphviz==2.40.1 \
         zlib ; \
     sync && \
     chmod -R a+rX /usr/local/miniconda; sync && \