diff --git a/science/libsbmlsim/Portfile b/science/libsbmlsim/Portfile
index b33ef6951b43d..82791ed6fa348 100644
--- a/science/libsbmlsim/Portfile
+++ b/science/libsbmlsim/Portfile
@@ -5,6 +5,7 @@ PortGroup           cmake 1.1
 PortGroup           github 1.0
 
 github.setup        libsbmlsim libsbmlsim 1.4.0 v
+revision            1
 categories          science
 platforms           darwin
 maintainers         {@funasoul gmail.com:funasoul} openmaintainer
@@ -36,24 +37,36 @@ variant java description {Generate Java language bindings.} {
     configure.args-append  -DWITH_JAVA:BOOL=ON
 }
 
-variant python27 conflicts python36 python37 description {Generate Python version 2.7 language bindings.} {
+variant python27 conflicts python36 python37 python38 python39 description {Generate Python version 2.7 language bindings.} {
     depends_build-append  port:swig port:swig-python
     depends_lib-append      port:python27
     configure.args-append   -DWITH_PYTHON:BOOL=ON -DPYTHON_EXECUTABLE=${prefix}/bin/python2.7
 }
 
-variant python36 conflicts python27 python37 description {Generate Python version 3.6 language bindings.} {
+variant python36 conflicts python27 python37 python38 python39 description {Generate Python version 3.6 language bindings.} {
     depends_build-append  port:swig port:swig-python
     depends_lib-append      port:python36
     configure.args-append   -DWITH_PYTHON:BOOL=ON -DPYTHON_EXECUTABLE=${prefix}/bin/python3.6
 }
 
-variant python37 conflicts python27 python36 description {Generate Python version 3.7 language bindings.} {
+variant python37 conflicts python27 python36 python38 python39 description {Generate Python version 3.7 language bindings.} {
     depends_build-append  port:swig port:swig-python
     depends_lib-append      port:python37
     configure.args-append   -DWITH_PYTHON:BOOL=ON -DPYTHON_EXECUTABLE=${prefix}/bin/python3.7
 }
 
+variant python38 conflicts python27 python36 python37 python39 description {Generate Python version 3.8 language bindings.} {
+    depends_build-append  port:swig port:swig-python
+    depends_lib-append      port:python38
+    configure.args-append   -DWITH_PYTHON:BOOL=ON -DPYTHON_EXECUTABLE=${prefix}/bin/python3.8
+}
+
+variant python39 conflicts python27 python36 python37 python38 description {Generate Python version 3.9 language bindings.} {
+    depends_build-append  port:swig port:swig-python
+    depends_lib-append      port:python39
+    configure.args-append   -DWITH_PYTHON:BOOL=ON -DPYTHON_EXECUTABLE=${prefix}/bin/python3.9
+}
+
 variant ruby description {Generate Ruby language bindings.} {
     depends_build-append   port:swig port:swig-ruby
     configure.args-append  -DWITH_RUBY:BOOL=ON