diff --git a/cmake/Modules/Documentation.cmake b/cmake/Modules/Documentation.cmake
index 6125155ad5..189c32e301 100644
--- a/cmake/Modules/Documentation.cmake
+++ b/cmake/Modules/Documentation.cmake
@@ -57,20 +57,14 @@ if(BUILD_DOC)
 
   # download mathjax distribution and unpack to folder "mathjax"
   if(NOT EXISTS ${DOC_BUILD_STATIC_DIR}/mathjax/es5)
-    file(DOWNLOAD "https://github.com/mathjax/MathJax/archive/3.0.5.tar.gz"
+    file(DOWNLOAD "https://github.com/mathjax/MathJax/archive/3.1.2.tar.gz"
       "${CMAKE_CURRENT_BINARY_DIR}/mathjax.tar.gz"
-      EXPECTED_MD5 5d9d3799cce77a1a95eee6be04eb68e7)
+      EXPECTED_MD5 a4a6a093a89bc2ccab1452d766b98e53)
     execute_process(COMMAND ${CMAKE_COMMAND} -E tar xzf mathjax.tar.gz WORKING_DIRECTORY ${CMAKE_CURRENT_BINARY_DIR})
     file(GLOB MATHJAX_VERSION_DIR ${CMAKE_CURRENT_BINARY_DIR}/MathJax-*)
     execute_process(COMMAND ${CMAKE_COMMAND} -E rename ${MATHJAX_VERSION_DIR} ${DOC_BUILD_STATIC_DIR}/mathjax)
   endif()
 
-  # for increased browser compatibility
-  if(NOT EXISTS ${DOC_BUILD_STATIC_DIR}/polyfill.js)
-    file(DOWNLOAD "https://polyfill.io/v3/polyfill.min.js?features=es6"
-      "${DOC_BUILD_STATIC_DIR}/polyfill.js")
-  endif()
-
   # set up doxygen and add targets to run it
   file(MAKE_DIRECTORY ${DOXYGEN_BUILD_DIR})
   file(COPY ${LAMMPS_DOC_DIR}/doxygen/lammps-logo.png DESTINATION ${DOXYGEN_BUILD_DIR}/lammps-logo.png)
diff --git a/doc/Makefile b/doc/Makefile
index 18fba1bab4..59700f03aa 100644
--- a/doc/Makefile
+++ b/doc/Makefile
@@ -14,7 +14,6 @@ TXT2RST        = $(VENV)/bin/txt2rst
 ANCHORCHECK    = $(VENV)/bin/rst_anchor_check
 SPHINXCONFIG   = $(BUILDDIR)/utils/sphinx-config
 MATHJAX        = $(SPHINXCONFIG)/_static/mathjax
-POLYFILL       = $(SPHINXCONFIG)/_static/polyfill.js
 
 PYTHON         = $(shell which python3)
 DOXYGEN        = $(shell which doxygen)
@@ -81,7 +80,7 @@ help:
 # ------------------------------------------
 
 clean-all: clean
-	rm -rf $(BUILDDIR)/docenv $(MATHJAX) $(POLYFILL) $(BUILDDIR)/LAMMPS.mobi $(BUILDDIR)/LAMMPS.epub $(BUILDDIR)/Manual.pdf
+	rm -rf $(BUILDDIR)/docenv $(MATHJAX) $(BUILDDIR)/LAMMPS.mobi $(BUILDDIR)/LAMMPS.epub $(BUILDDIR)/Manual.pdf
 
 clean: clean-spelling
 	rm -rf $(BUILDDIR)/html $(BUILDDIR)/epub $(BUILDDIR)/latex $(BUILDDIR)/doctrees $(BUILDDIR)/doxygen/xml $(BUILDDIR)/doxygen-warn.log $(BUILDDIR)/doxygen/Doxyfile $(SPHINXCONFIG)/conf.py
@@ -95,7 +94,7 @@ $(SPHINXCONFIG)/conf.py: $(SPHINXCONFIG)/conf.py.in
 	    -e 's,@LAMMPS_PYTHON_DIR@,$(BUILDDIR)/../python,g' \
 	    -e 's,@LAMMPS_DOC_DIR@,$(BUILDDIR),g' $< > $@
 
-html: xmlgen $(SPHINXCONFIG)/conf.py $(ANCHORCHECK) $(MATHJAX) $(POLYFILL)
+html: xmlgen $(SPHINXCONFIG)/conf.py $(ANCHORCHECK) $(MATHJAX)
 	@if [ "$(HAS_BASH)" == "NO" ] ; then echo "bash was not found at $(OSHELL)! Please use: $(MAKE) SHELL=/path/to/bash" 1>&2; exit 1; fi
 	@$(MAKE) $(MFLAGS) -C graphviz all
 	@(\
@@ -237,13 +236,6 @@ $(VENV):
 $(MATHJAX):
 	@git clone --depth 1 https://github.com/mathjax/MathJax.git $@
 
-# fall back to using wget and/or unencrypted download, if curl fails
-$(POLYFILL): $(MATHJAX)
-	@curl -s -o $@ "https://polyfill.io/v3/polyfill.min.js?features=es6" > /dev/null 2>&1  || \
-		curl -s -o $@ "http://polyfill.io/v3/polyfill.min.js?features=es6" > /dev/null 2>&1  || \
-		wget -O $@ "https://polyfill.io/v3/polyfill.min.js?features=es6" > /dev/null 2>&1  || \
-		wget -O $@ "http://polyfill.io/v3/polyfill.min.js?features=es6" > /dev/null 2>&1
-
 $(TXT2RST) $(ANCHORCHECK): $(VENV)
 	@( \
 		. $(VENV)/bin/activate; \
diff --git a/doc/src/Build_manual.rst b/doc/src/Build_manual.rst
index 129e256cfd..59e4e3235b 100644
--- a/doc/src/Build_manual.rst
+++ b/doc/src/Build_manual.rst
@@ -73,8 +73,8 @@ after the documentation folder is returned to a pristine state with
 For the documentation build a python virtual environment is set up in
 the folder ``doc/docenv`` and various python packages are installed into
 that virtual environment via the ``pip`` tool.  For rendering embedded
-LaTeX code also the `MathJax <https://www.mathjax.org/>`_ and the
-`Polyfill <https://polyfill.io/>`_ JavaScript engines need to be downloaded.
+LaTeX code also the `MathJax <https://www.mathjax.org/>`_ JavaScript
+engine needs to be downloaded.
 
 The actual translation is then done via ``make`` commands in the doc
 folder.  The following ``make`` commands are available:
diff --git a/doc/utils/sphinx-config/_themes/lammps_theme/layout.html b/doc/utils/sphinx-config/_themes/lammps_theme/layout.html
index 98d25ebca1..845f213a4c 100644
--- a/doc/utils/sphinx-config/_themes/lammps_theme/layout.html
+++ b/doc/utils/sphinx-config/_themes/lammps_theme/layout.html
@@ -52,11 +52,6 @@
   {# Keep modernizr in head - http://modernizr.com/docs/#installing #}
   <script src="{{ pathto('_static/js/modernizr.min.js', 1) }}"></script>
 
-  {# for improved browser compatibility #}
-  <!--[if lte IE 11]>
-    <script src="{{ pathto('_static/polyfill.js', 1) }}"></script>
-  <![endif]-->
-
   {%- if not embedded %}
   {# XXX Sphinx 1.8.0 made this an external js-file, quick fix until we refactor the template to inherert more blocks directly from sphinx #}
     {% if sphinx_version >= "1.8.0" %}