diff --git a/Makefile b/Makefile
index 95f52f6..faeb099 100644
--- a/Makefile
+++ b/Makefile
@@ -11,8 +11,6 @@ check: ## Run code quality tools.
 	@poetry lock --check
 	@echo "🚀 Linting code: Running pre-commit"
 	@poetry run pre-commit run -a
-	@echo "🚀 Checking for obsolete dependencies: Running deptry"
-	@poetry run deptry .
 
 .PHONY: test
 test: ## Test the code with pytest
diff --git a/json_explorer/explore.py b/json_explorer/explore.py
index 18f973f..55cdba1 100644
--- a/json_explorer/explore.py
+++ b/json_explorer/explore.py
@@ -29,6 +29,20 @@ def oxford_join(items, pluralize=False):
     return "{}, or {}".format(", ".join(items[:-1]), items[-1])
 
 
+class Counter(collections.Counter):
+    """The 'total' method is only available on a collections.Counter
+    in python >= 3.10, so add the method to be compatible with earlier
+    versions.
+
+    """
+
+    def total(self):
+        try:
+            return super().total()
+        except AttributeError:
+            return sum(self.values())
+
+
 class TripleCounter(dict):
     def increment(self, keys, amount):
         try:
@@ -40,13 +54,13 @@ def increment(self, keys, amount):
         if a not in self:
             self[a] = {}
         if b not in self[a]:
-            self[a][b] = collections.Counter()
+            self[a][b] = Counter()
         self[a][b][c] += amount
 
     def tree(self):
         result = {}
         for a, sub_dict in self.items():
-            sub_counter = collections.Counter()
+            sub_counter = Counter()
             for b, c_counter in sub_dict.items():
                 sub_counter[b] += c_counter.total()
 
diff --git a/poetry.lock b/poetry.lock
index c4be43e..edc1aaa 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -18,6 +18,17 @@ soupsieve = ">1.2"
 html5lib = ["html5lib"]
 lxml = ["lxml"]
 
+[[package]]
+name = "cached-property"
+version = "1.5.2"
+description = "A decorator for caching properties in classes."
+optional = false
+python-versions = "*"
+files = [
+    {file = "cached-property-1.5.2.tar.gz", hash = "sha256:9fa5755838eecbb2d234c3aa390bd80fbd3ac6b6869109bfc1b499f7bd89a130"},
+    {file = "cached_property-1.5.2-py2.py3-none-any.whl", hash = "sha256:df4f613cf7ad9a588cc381aaf4a512d26265ecebd5eb9e1ba12f1319eb85a6a0"},
+]
+
 [[package]]
 name = "certifi"
 version = "2023.5.7"
@@ -40,17 +51,6 @@ files = [
     {file = "cfgv-3.3.1.tar.gz", hash = "sha256:f5a830efb9ce7a445376bb66ec94c638a9787422f96264c98edc6bdeed8ab736"},
 ]
 
-[[package]]
-name = "chardet"
-version = "5.1.0"
-description = "Universal encoding detector for Python 3"
-optional = false
-python-versions = ">=3.7"
-files = [
-    {file = "chardet-5.1.0-py3-none-any.whl", hash = "sha256:362777fb014af596ad31334fde1e8c327dfdb076e1960d1694662d46a6917ab9"},
-    {file = "chardet-5.1.0.tar.gz", hash = "sha256:0d62712b956bc154f85fb0a266e2a3c5913c2967e00348701b32411d6def31e5"},
-]
-
 [[package]]
 name = "charset-normalizer"
 version = "3.1.0"
@@ -148,6 +148,7 @@ files = [
 
 [package.dependencies]
 colorama = {version = "*", markers = "platform_system == \"Windows\""}
+importlib-metadata = {version = "*", markers = "python_version < \"3.8\""}
 
 [[package]]
 name = "colorama"
@@ -235,22 +236,6 @@ tomli = {version = "*", optional = true, markers = "python_full_version <= \"3.1
 [package.extras]
 toml = ["tomli"]
 
-[[package]]
-name = "deptry"
-version = "0.6.6"
-description = "A command line utility to check for obsolete, missing and transitive dependencies in a Python project."
-optional = false
-python-versions = ">=3.7,<4.0"
-files = [
-    {file = "deptry-0.6.6-py3-none-any.whl", hash = "sha256:38c03085899339a43374ba51c845d6d1e3d3d2d003d8270d85f0c67f19775e36"},
-    {file = "deptry-0.6.6.tar.gz", hash = "sha256:b968b459929ede5428d695c801f39d03c058de7fa7f855585ca8620a1ec3ae62"},
-]
-
-[package.dependencies]
-chardet = ">=4.0.0"
-click = ">=8.0.0,<9.0.0"
-tomli = {version = ">=2.0.1,<3.0.0", markers = "python_version < \"3.11\""}
-
 [[package]]
 name = "distlib"
 version = "0.3.6"
@@ -320,6 +305,7 @@ files = [
 ]
 
 [package.dependencies]
+cached-property = {version = "*", markers = "python_version < \"3.8\""}
 colorama = ">=0.4"
 
 [[package]]
@@ -359,6 +345,7 @@ files = [
 ]
 
 [package.dependencies]
+typing-extensions = {version = ">=3.6.4", markers = "python_version < \"3.8\""}
 zipp = ">=0.5"
 
 [package.extras]
@@ -503,6 +490,7 @@ mergedeep = ">=1.3.4"
 packaging = ">=20.5"
 pyyaml = ">=5.1"
 pyyaml-env-tag = ">=0.1"
+typing-extensions = {version = ">=3.10", markers = "python_version < \"3.8\""}
 watchdog = ">=2.0"
 
 [package.extras]
@@ -631,6 +619,9 @@ files = [
     {file = "platformdirs-3.5.1.tar.gz", hash = "sha256:412dae91f52a6f84830f39a8078cecd0e866cb72294a5c66808e74d5e88d251f"},
 ]
 
+[package.dependencies]
+typing-extensions = {version = ">=4.5", markers = "python_version < \"3.8\""}
+
 [package.extras]
 docs = ["furo (>=2023.3.27)", "proselint (>=0.13)", "sphinx (>=6.2.1)", "sphinx-autodoc-typehints (>=1.23,!=1.23.4)"]
 test = ["appdirs (==1.4.4)", "covdefaults (>=2.3)", "pytest (>=7.3.1)", "pytest-cov (>=4)", "pytest-mock (>=3.10)"]
@@ -646,6 +637,9 @@ files = [
     {file = "pluggy-1.0.0.tar.gz", hash = "sha256:4224373bacce55f955a878bf9cfa763c1e360858e330072059e10bad68531159"},
 ]
 
+[package.dependencies]
+importlib-metadata = {version = ">=0.12", markers = "python_version < \"3.8\""}
+
 [package.extras]
 dev = ["pre-commit", "tox"]
 testing = ["pytest", "pytest-benchmark"]
@@ -664,6 +658,7 @@ files = [
 [package.dependencies]
 cfgv = ">=2.0.0"
 identify = ">=1.0.0"
+importlib-metadata = {version = "*", markers = "python_version < \"3.8\""}
 nodeenv = ">=0.11.1"
 pyyaml = ">=5.1"
 virtualenv = ">=20.10.0"
@@ -722,6 +717,7 @@ files = [
 [package.dependencies]
 colorama = {version = "*", markers = "sys_platform == \"win32\""}
 exceptiongroup = {version = ">=1.0.0rc8", markers = "python_version < \"3.11\""}
+importlib-metadata = {version = ">=0.12", markers = "python_version < \"3.8\""}
 iniconfig = "*"
 packaging = "*"
 pluggy = ">=0.12,<2.0"
@@ -909,6 +905,7 @@ files = [
 [package.dependencies]
 colorama = {version = ">=0.4.1", markers = "platform_system == \"Windows\""}
 filelock = ">=3.0.0"
+importlib-metadata = {version = ">=0.12", markers = "python_version < \"3.8\""}
 packaging = ">=14"
 pluggy = ">=0.12.0"
 py = ">=1.4.17"
@@ -920,6 +917,17 @@ virtualenv = ">=16.0.0,<20.0.0 || >20.0.0,<20.0.1 || >20.0.1,<20.0.2 || >20.0.2,
 docs = ["pygments-github-lexers (>=0.0.5)", "sphinx (>=2.0.0)", "sphinxcontrib-autoprogram (>=0.1.5)", "towncrier (>=18.5.0)"]
 testing = ["flaky (>=3.4.0)", "freezegun (>=0.3.11)", "pathlib2 (>=2.3.3)", "psutil (>=5.6.1)", "pytest (>=4.0.0)", "pytest-cov (>=2.5.1)", "pytest-mock (>=1.10.0)", "pytest-randomly (>=1.0.0)"]
 
+[[package]]
+name = "typing-extensions"
+version = "4.6.3"
+description = "Backported and Experimental Type Hints for Python 3.7+"
+optional = false
+python-versions = ">=3.7"
+files = [
+    {file = "typing_extensions-4.6.3-py3-none-any.whl", hash = "sha256:88a4153d8505aabbb4e13aacb7c486c2b4a33ca3b3f807914a9b4c844c471c26"},
+    {file = "typing_extensions-4.6.3.tar.gz", hash = "sha256:d91d5919357fe7f681a9f2b5b4cb2a5f1ef0a1e9f59c4d8ff0d3491e05c0ffd5"},
+]
+
 [[package]]
 name = "urllib3"
 version = "2.0.2"
@@ -951,6 +959,7 @@ files = [
 [package.dependencies]
 distlib = ">=0.3.6,<1"
 filelock = ">=3.11,<4"
+importlib-metadata = {version = ">=6.4.1", markers = "python_version < \"3.8\""}
 platformdirs = ">=3.2,<4"
 
 [package.extras]
@@ -1013,5 +1022,5 @@ testing = ["big-O", "flake8 (<5)", "jaraco.functools", "jaraco.itertools", "more
 
 [metadata]
 lock-version = "2.0"
-python-versions = ">=3.8,<4.0"
-content-hash = "465c368f25da133d7e7257e2df45512ef2756b4e00f50a2507ebc27975b6e837"
+python-versions = ">=3.7,<4.0"
+content-hash = "57645037ea0f29f6e9770808db1b6f86ec3397ca8ceb544e95976b1497a8d9bf"
diff --git a/pyproject.toml b/pyproject.toml
index 6cc732d..84d4488 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -14,12 +14,11 @@ packages = [
 greet = "json_explorer.explore:main"
 
 [tool.poetry.dependencies]
-python = ">=3.8,<4.0"
+python = ">=3.7,<4.0"
 
 [tool.poetry.group.dev.dependencies]
 pytest = "^7.2.0"
 pytest-cov = "^4.0.0"
-deptry = "^0.6.4"
 pre-commit = "^2.20.0"
 tox = "^3.25.1"
 beautifulsoup4 = "^4.12.2"
diff --git a/tox.ini b/tox.ini
index 6953a07..a004993 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,9 +1,10 @@
 [tox]
 skipsdist = true
-envlist = py38, py39, py310, py311
+envlist = py37, py38, py39, py310, py311
 
 [gh-actions]
 python =
+    3.7: py37
     3.8: py38
     3.9: py39
     3.10: py310