diff --git a/poetry.lock b/poetry.lock
index dab156db..3115b72f 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -919,7 +919,7 @@ docs = ["furo", "sphinx"]
 
 [[package]]
 name = "furo"
-version = "2021.6.18b36"
+version = "2021.8.31"
 description = "A clean customisable Sphinx documentation theme."
 category = "dev"
 optional = false
@@ -927,10 +927,10 @@ python-versions = ">=3.6"
 
 [package.dependencies]
 beautifulsoup4 = "*"
-sphinx = ">=3.0,<5.0"
+sphinx = ">=4.0,<5.0"
 
 [package.extras]
-doc = ["myst-parser", "sphinx-copybutton", "sphinx-inline-tabs", "docutils (!=0.17)"]
+doc = ["myst-parser", "sphinx-copybutton", "sphinx-design", "sphinx-inline-tabs"]
 test = ["pytest", "pytest-cov", "pytest-xdist"]
 
 [[package]]
@@ -1700,22 +1700,23 @@ testing = ["coverage", "pyyaml"]
 
 [[package]]
 name = "markdown-it-py"
-version = "0.6.2"
+version = "1.1.0"
 description = "Python port of markdown-it. Markdown parsing, done right!"
 category = "dev"
 optional = false
 python-versions = "~=3.6"
 
 [package.dependencies]
-attrs = ">=19,<21"
-mdit-py-plugins = ">=0.2.1,<0.3.0"
+attrs = ">=19,<22"
+typing-extensions = {version = ">=3.7.4", markers = "python_version < \"3.8\""}
 
 [package.extras]
 code_style = ["pre-commit (==2.6)"]
-compare = ["commonmark (>=0.9.1,<0.10.0)", "markdown (>=3.2.2,<3.3.0)", "mistune (>=0.8.4,<0.9.0)", "mistletoe-ebp (>=0.10.0,<0.11.0)", "panflute (>=1.12,<2.0)"]
+compare = ["commonmark (>=0.9.1,<0.10.0)", "markdown (>=3.2.2,<3.3.0)", "mistletoe-ebp (>=0.10.0,<0.11.0)", "mistune (>=0.8.4,<0.9.0)", "panflute (>=1.12,<2.0)"]
 linkify = ["linkify-it-py (>=1.0,<2.0)"]
-rtd = ["myst-nb (>=0.11.1,<0.12.0)", "sphinx-book-theme", "sphinx-panels (>=0.4.0,<0.5.0)", "sphinx-copybutton", "sphinx (>=2,<4)", "pyyaml"]
-testing = ["coverage", "pytest (>=3.6,<4)", "pytest-cov", "pytest-regressions", "pytest-benchmark (>=3.2,<4.0)", "psutil"]
+plugins = ["mdit-py-plugins"]
+rtd = ["myst-nb (==0.13.0a1)", "pyyaml", "sphinx (>=2,<4)", "sphinx-copybutton", "sphinx-panels (>=0.4.0,<0.5.0)", "sphinx-book-theme"]
+testing = ["coverage", "psutil", "pytest (>=3.6,<4)", "pytest-benchmark (>=3.2,<4.0)", "pytest-cov", "pytest-regressions"]
 
 [[package]]
 name = "markupsafe"
@@ -1754,17 +1755,18 @@ traitlets = "*"
 
 [[package]]
 name = "mdit-py-plugins"
-version = "0.2.6"
+version = "0.2.8"
 description = "Collection of plugins for markdown-it-py"
 category = "dev"
 optional = false
 python-versions = "~=3.6"
 
 [package.dependencies]
-markdown-it-py = ">=0.5.8,<2.0.0"
+markdown-it-py = ">=1.0,<2.0"
 
 [package.extras]
 code_style = ["pre-commit (==2.6)"]
+rtd = ["myst-parser (==0.14.0a3)", "sphinx-book-theme (>=0.1.0,<0.2.0)"]
 testing = ["coverage", "pytest (>=3.6,<4)", "pytest-cov", "pytest-regressions"]
 
 [[package]]
@@ -1824,34 +1826,34 @@ python-versions = "*"
 
 [[package]]
 name = "myst-nb"
-version = "0.12.3"
+version = "0.13.0"
 description = "A Jupyter Notebook Sphinx reader built on top of the MyST markdown parser."
 category = "dev"
 optional = false
 python-versions = ">=3.6"
 
 [package.dependencies]
-docutils = ">=0.15"
+docutils = ">=0.15,<0.18"
 importlib-metadata = "*"
 ipython = "*"
 ipywidgets = ">=7.0.0,<8"
 jupyter-cache = ">=0.4.1,<0.5.0"
 jupyter-sphinx = ">=0.3.2,<0.4.0"
-myst-parser = ">=0.13.5,<0.14.0"
-nbconvert = ">=5.6,<6.0"
+myst-parser = ">=0.15.2,<0.16.0"
+nbconvert = ">=5.6,<7"
 nbformat = ">=5.0,<6.0"
 pyyaml = "*"
-sphinx = ">=2,<4"
+sphinx = ">=3.1,<5"
 sphinx-togglebutton = ">=0.2.2,<0.3.0"
 
 [package.extras]
 code_style = ["pre-commit (>=2.12,<3.0)"]
-rtd = ["alabaster", "altair", "bokeh", "coconut (>=1.4.3,<1.5.0)", "ipywidgets", "jupytext (>=1.8.0,<1.9.0)", "matplotlib", "numpy", "pandas", "plotly", "sphinx-book-theme (>=0.1.0,<0.2.0)", "sphinx-copybutton", "sphinx-panels (>=0.4.1,<0.5.0)", "sphinxcontrib-bibtex", "sympy"]
-testing = ["coverage (<5.0)", "jupytext (>=1.8.0,<1.9.0)", "matplotlib (>=3.3.0,<3.4.0)", "numpy", "pandas", "pytest (>=5.4,<6.0)", "pytest-cov (>=2.8,<3.0)", "pytest-regressions", "sympy"]
+rtd = ["alabaster", "altair", "bokeh", "coconut (>=1.4.3,<1.5.0)", "ipykernel (>=5.5,<6.0)", "ipywidgets", "jupytext (>=1.11.2,<1.12.0)", "matplotlib", "numpy", "pandas", "plotly", "sphinx-book-theme (>=0.1.0,<0.2.0)", "sphinx-copybutton", "sphinx-panels (>=0.4.1,<0.5.0)", "sphinxcontrib-bibtex", "sympy"]
+testing = ["coverage (<5.0)", "ipykernel (>=5.5,<6.0)", "jupytext (>=1.11.2,<1.12.0)", "matplotlib (>=3.3.0,<3.4.0)", "numpy", "pandas", "pytest (>=5.4,<6.0)", "pytest-cov (>=2.8,<3.0)", "pytest-regressions", "sympy"]
 
 [[package]]
 name = "myst-parser"
-version = "0.13.7"
+version = "0.15.2"
 description = "An extended commonmark compliant parser, with bridges to docutils & sphinx."
 category = "dev"
 optional = false
@@ -1860,15 +1862,15 @@ python-versions = ">=3.6"
 [package.dependencies]
 docutils = ">=0.15,<0.18"
 jinja2 = "*"
-markdown-it-py = ">=0.6.2,<0.7.0"
-mdit-py-plugins = ">=0.2.5,<0.3.0"
+markdown-it-py = ">=1.0.0,<2.0.0"
+mdit-py-plugins = ">=0.2.8,<0.3.0"
 pyyaml = "*"
-sphinx = ">=2.1,<4"
+sphinx = ">=3.1,<5"
 
 [package.extras]
 code_style = ["pre-commit (>=2.12,<3.0)"]
 linkify = ["linkify-it-py (>=1.0,<2.0)"]
-rtd = ["ipython", "sphinx-book-theme (>=0.1.0,<0.2.0)", "sphinx-panels (>=0.5.2,<0.6.0)", "sphinxcontrib-bibtex (>=2.1,<3.0)"]
+rtd = ["ipython", "sphinx-book-theme (>=0.1.0,<0.2.0)", "sphinx-panels (>=0.5.2,<0.6.0)", "sphinxcontrib-bibtex (>=2.1,<3.0)", "sphinxext-rediraffe (>=0.2,<1.0)", "sphinxcontrib.mermaid (>=0.6.3,<0.7.0)", "sphinxext-opengraph (>=0.4.2,<0.5.0)"]
 testing = ["beautifulsoup4", "coverage", "docutils (>=0.17.0,<0.18.0)", "pytest (>=3.6,<4)", "pytest-cov", "pytest-regressions"]
 
 [[package]]
@@ -3007,17 +3009,17 @@ th = ["pythainlp (>=2.0)"]
 
 [[package]]
 name = "sphinx"
-version = "3.5.4"
+version = "4.1.2"
 description = "Python documentation generator"
 category = "main"
 optional = false
-python-versions = ">=3.5"
+python-versions = ">=3.6"
 
 [package.dependencies]
 alabaster = ">=0.7,<0.8"
 babel = ">=1.3"
 colorama = {version = ">=0.3.5", markers = "sys_platform == \"win32\""}
-docutils = ">=0.12,<0.17"
+docutils = ">=0.14,<0.18"
 imagesize = "*"
 Jinja2 = ">=2.3"
 packaging = "*"
@@ -3026,14 +3028,14 @@ requests = ">=2.5.0"
 snowballstemmer = ">=1.1"
 sphinxcontrib-applehelp = "*"
 sphinxcontrib-devhelp = "*"
-sphinxcontrib-htmlhelp = "*"
+sphinxcontrib-htmlhelp = ">=2.0.0"
 sphinxcontrib-jsmath = "*"
 sphinxcontrib-qthelp = "*"
-sphinxcontrib-serializinghtml = "*"
+sphinxcontrib-serializinghtml = ">=1.1.5"
 
 [package.extras]
 docs = ["sphinxcontrib-websupport"]
-lint = ["flake8 (>=3.5.0)", "isort", "mypy (>=0.800)", "docutils-stubs"]
+lint = ["flake8 (>=3.5.0)", "isort", "mypy (>=0.900)", "docutils-stubs", "types-typed-ast", "types-pkg-resources", "types-requests"]
 test = ["pytest", "pytest-cov", "html5lib", "cython", "typed-ast"]
 
 [[package]]
@@ -3722,7 +3724,7 @@ webserver = ["pymongo", "sentry-sdk", "flask"]
 [metadata]
 lock-version = "1.1"
 python-versions = ">=3.7.1,<3.10"
-content-hash = "ded52ce06291106551b98b38acf2487218b424e682258401ebb8281c62a3fe22"
+content-hash = "34de66a175229e9f79bed51dcd8f2609b3da3946f8762c9e7296e29f4b1e183f"
 
 [metadata.files]
 absl-py = [
@@ -4251,8 +4253,8 @@ ftfy = [
     {file = "ftfy-6.0.3.tar.gz", hash = "sha256:ba71121a9c8d7790d3e833c6c1021143f3e5c4118293ec3afb5d43ed9ca8e72b"},
 ]
 furo = [
-    {file = "furo-2021.6.18b36-py3-none-any.whl", hash = "sha256:a4c00634afeb5896a34d141a5dffb62f20c5eca7831b78269823a8cd8b09a5e4"},
-    {file = "furo-2021.6.18b36.tar.gz", hash = "sha256:46a30bc597a9067088d39d730e7d9bf6c1a1d71967e4af062f796769f66b3bdb"},
+    {file = "furo-2021.8.31-py3-none-any.whl", hash = "sha256:15f659b328f206093151d86210a49a4ce4185a5945bc3d19b1202e45d55fb54e"},
+    {file = "furo-2021.8.31.tar.gz", hash = "sha256:1dd84b7594d8798e6d7e7e9fb502f5407943060047e87a9c75964afeea113b4e"},
 ]
 future = [
     {file = "future-0.18.2.tar.gz", hash = "sha256:b1bead90b70cf6ec3f0710ae53a525360fa360d306a86583adc6bf83a4db537d"},
@@ -4694,8 +4696,8 @@ markdown = [
     {file = "Markdown-3.3.4.tar.gz", hash = "sha256:31b5b491868dcc87d6c24b7e3d19a0d730d59d3e46f4eea6430a321bed387a49"},
 ]
 markdown-it-py = [
-    {file = "markdown-it-py-0.6.2.tar.gz", hash = "sha256:c3b9f995be0792cbbc8ab2f53d74072eb7ff8a8b622be8d61d38ab879709eca3"},
-    {file = "markdown_it_py-0.6.2-py3-none-any.whl", hash = "sha256:30b3e9f8198dc82a5df0dcb73fd31d56cd9a43bf8a747feb10b2ba74f962bcb1"},
+    {file = "markdown-it-py-1.1.0.tar.gz", hash = "sha256:36be6bb3ad987bfdb839f5ba78ddf094552ca38ccbd784ae4f74a4e1419fc6e3"},
+    {file = "markdown_it_py-1.1.0-py3-none-any.whl", hash = "sha256:98080fc0bc34c4f2bcf0846a096a9429acbd9d5d8e67ed34026c03c61c464389"},
 ]
 markupsafe = [
     {file = "MarkupSafe-2.0.1-cp36-cp36m-macosx_10_9_x86_64.whl", hash = "sha256:f9081981fe268bd86831e5c75f7de206ef275defcb82bc70740ae6dc507aee51"},
@@ -4761,8 +4763,8 @@ matplotlib-inline = [
     {file = "matplotlib_inline-0.1.2-py3-none-any.whl", hash = "sha256:5cf1176f554abb4fa98cb362aa2b55c500147e4bdbb07e3fda359143e1da0811"},
 ]
 mdit-py-plugins = [
-    {file = "mdit-py-plugins-0.2.6.tar.gz", hash = "sha256:1e467ca2ea056e8065cbd5d6c61e5052bb50826bde84c40f6a5ed77e82125710"},
-    {file = "mdit_py_plugins-0.2.6-py3-none-any.whl", hash = "sha256:77fd75dad81109ee91f30eb49146196f79afbbae041f298ae4886c8c2b5e23d7"},
+    {file = "mdit-py-plugins-0.2.8.tar.gz", hash = "sha256:5991cef645502e80a5388ec4fc20885d2313d4871e8b8e320ca2de14ac0c015f"},
+    {file = "mdit_py_plugins-0.2.8-py3-none-any.whl", hash = "sha256:1833bf738e038e35d89cb3a07eb0d227ed647ce7dd357579b65343740c6d249c"},
 ]
 mistune = [
     {file = "mistune-0.8.4-py2.py3-none-any.whl", hash = "sha256:88a1051873018da288eee8538d476dffe1262495144b33ecb586c4ab266bb8d4"},
@@ -4840,12 +4842,12 @@ mypy-extensions = [
     {file = "mypy_extensions-0.4.3.tar.gz", hash = "sha256:2d82818f5bb3e369420cb3c4060a7970edba416647068eb4c5343488a6c604a8"},
 ]
 myst-nb = [
-    {file = "myst-nb-0.12.3.tar.gz", hash = "sha256:4666039f538abf32d6489f4caf912d505e8798a2709bcf7a7936823ca6b15810"},
-    {file = "myst_nb-0.12.3-py3-none-any.whl", hash = "sha256:3bc5191494720748419b8247e9ffc92d39b4ea7689f92d937e65110b346403fd"},
+    {file = "myst-nb-0.13.0.tar.gz", hash = "sha256:3a138b4ac368b2b95b0c3a007c237cdca718f9cc665dcfba3401b1635e89e4f2"},
+    {file = "myst_nb-0.13.0-py3-none-any.whl", hash = "sha256:07f1cdfe7c81fc6a4b963f04027cf3b27a6fcbb6d5bfec966859c38ec8bf744c"},
 ]
 myst-parser = [
-    {file = "myst-parser-0.13.7.tar.gz", hash = "sha256:e4bc99e43e19f70d22e528de8e7cce59f7e8e7c4c34dcba203de92de7a7c7c85"},
-    {file = "myst_parser-0.13.7-py3-none-any.whl", hash = "sha256:260355b4da8e8865fe080b0638d7f1ab1791dc4bed02a7a48630b6bad4249219"},
+    {file = "myst-parser-0.15.2.tar.gz", hash = "sha256:f7f3b2d62db7655cde658eb5d62b2ec2a4631308137bd8d10f296a40d57bbbeb"},
+    {file = "myst_parser-0.15.2-py3-none-any.whl", hash = "sha256:40124b6f27a4c42ac7f06b385e23a9dcd03d84801e9c7130b59b3729a554b1f9"},
 ]
 nbclient = [
     {file = "nbclient-0.5.4-py3-none-any.whl", hash = "sha256:95a300c6fbe73721736cf13972a46d8d666f78794b832866ed7197a504269e11"},
@@ -5684,8 +5686,8 @@ spacy = [
     {file = "spacy-2.3.7.tar.gz", hash = "sha256:c0f2315fea23497662e28212f89af3a03667f97c867c597b599c37ab84092e22"},
 ]
 sphinx = [
-    {file = "Sphinx-3.5.4-py3-none-any.whl", hash = "sha256:2320d4e994a191f4b4be27da514e46b3d6b420f2ff895d064f52415d342461e8"},
-    {file = "Sphinx-3.5.4.tar.gz", hash = "sha256:19010b7b9fa0dc7756a6e105b2aacd3a80f798af3c25c273be64d7beeb482cb1"},
+    {file = "Sphinx-4.1.2-py3-none-any.whl", hash = "sha256:46d52c6cee13fec44744b8c01ed692c18a640f6910a725cbb938bc36e8d64544"},
+    {file = "Sphinx-4.1.2.tar.gz", hash = "sha256:3092d929cd807926d846018f2ace47ba2f3b671b309c7a89cd3306e80c826b13"},
 ]
 sphinx-copybutton = [
     {file = "sphinx-copybutton-0.4.0.tar.gz", hash = "sha256:8daed13a87afd5013c3a9af3575cc4d5bec052075ccd3db243f895c07a689386"},
diff --git a/pyproject.toml b/pyproject.toml
index bcbfb41b..72f6f93e 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -86,26 +86,26 @@ all = ["bio-embeddings-allennlp", "transformers", "jax-unirep", "fair-esm", "bio
 webserver = ["pymongo", "sentry-sdk", "flask"]
 
 [tool.poetry.dev-dependencies]
-pytest = "^6.0.1"
-invoke = "^1.4.1"
-check-manifest = "^0.41"
-wheel = "^0.34.2"
-jupyter = "^1.0.0"
-tox = "^3.16.1"
 black = "21.8b0"
-toml = "^0.10.1"
-furo = "^2021.2.28b28"
-Sphinx = "^3.2.1" # Sphinx 4 is blocked on https://github.com/executablebooks/MyST-NB/issues/338
-myst-parser = "^0.13.5"
-myst-nb = "^0.12.0"
-sphinx-copybutton = "^0.4.0"
-mongomock = "^3.22.0"
-pytest-flask = "^1.1.0"
-pytest-celery = "^0.0.0-alpha.1"
+check-manifest = "^0.41"
 flask-restx = "^0.5.0"
-packaging = "^20.8"
+furo = "^2021.08.31"
 hypothesis = "^6.3.4"
 hypothesis-bio = { git = "https://github.com/IQTLabs/hypothesis-bio", rev = "393f080772ae7aa7ca0358ce1a6753c0b69546e2" }
+invoke = "^1.4.1"
+jupyter = "^1.0.0"
+mongomock = "^3.22.0"
+myst-nb = "^0.13.0"
+myst-parser = "^0.15.2"
+packaging = "^20.8"
+pytest = "^6.0.1"
+pytest-celery = "^0.0.0-alpha.1"
+pytest-flask = "^1.1.0"
+sphinx = "^4"
+sphinx-copybutton = "^0.4.0"
+toml = "^0.10.1"
+tox = "^3.16.1"
+wheel = "^0.34.2"
 
 [tool.pytest.ini_options]
 addopts = "--tb=short"