diff --git a/.github/workflows/ci-tests.yml b/.github/workflows/ci-tests.yml
index ef178eacd..f2f53b8bf 100644
--- a/.github/workflows/ci-tests.yml
+++ b/.github/workflows/ci-tests.yml
@@ -32,8 +32,18 @@ jobs:
     strategy:
       matrix:
         py-ver-major: [3]
-        py-ver-minor: [8, 9, 10, 11, 12]
+        py-ver-minor: [7, 8, 9, 10, 11, 12]
         step: [lint, unit, bandit, mypy]
+        exclude:
+          - py-ver-major: 3
+            py-ver-minor: 7
+            step: mypy
+          - py-ver-major: 3
+            py-ver-minor: 7
+            step: lint
+          - py-ver-major: 3
+            py-ver-minor: 7
+            step: bandit
 
     env:
       py-semver: ${{ format('{0}.{1}', matrix.py-ver-major, matrix.py-ver-minor) }}
diff --git a/cwltool/checker.py b/cwltool/checker.py
index c11561719..1132adebe 100644
--- a/cwltool/checker.py
+++ b/cwltool/checker.py
@@ -5,7 +5,6 @@
     Dict,
     Iterator,
     List,
-    Literal,
     MutableMapping,
     MutableSequence,
     Optional,
@@ -13,6 +12,7 @@
     Union,
     cast,
 )
+from typing_extensions import Literal
 
 from schema_salad.exceptions import ValidationException
 from schema_salad.sourceline import SourceLine, bullets, strip_dup_lineno
@@ -509,7 +509,8 @@ def get_step_id(field_id: str) -> str:
 
 
 def is_conditional_step(param_to_step: Dict[str, CWLObjectType], parm_id: str) -> bool:
-    if (source_step := param_to_step.get(parm_id)) is not None:
+    source_step = param_to_step.get(parm_id)
+    if source_step is not None:
         if source_step.get("when") is not None:
             return True
     return False
diff --git a/cwltool/context.py b/cwltool/context.py
index 7f30e4c30..d0bf98a07 100644
--- a/cwltool/context.py
+++ b/cwltool/context.py
@@ -12,12 +12,12 @@
     Dict,
     Iterable,
     List,
-    Literal,
     Optional,
     TextIO,
     Tuple,
     Union,
 )
+from typing_extensions import Literal
 
 from ruamel.yaml.comments import CommentedMap
 from schema_salad.avro.schema import Names
diff --git a/cwltool/cwlprov/__init__.py b/cwltool/cwlprov/__init__.py
index b8ff8d14d..b7db6ab33 100644
--- a/cwltool/cwlprov/__init__.py
+++ b/cwltool/cwlprov/__init__.py
@@ -6,7 +6,8 @@
 import re
 import uuid
 from getpass import getuser
-from typing import IO, Any, Callable, Dict, List, Optional, Tuple, TypedDict, Union
+from typing import IO, Any, Callable, Dict, List, Optional, Tuple, Union
+from typing_extensions import TypedDict
 
 
 def _whoami() -> Tuple[str, str]:
diff --git a/cwltool/software_requirements.py b/cwltool/software_requirements.py
index 4587b97a8..7e114bb86 100644
--- a/cwltool/software_requirements.py
+++ b/cwltool/software_requirements.py
@@ -91,8 +91,9 @@ def build_job_script(self, builder: "Builder", command: List[str]) -> str:
             resolution_config_dict=resolution_config_dict,
             conf_file=self.dependency_resolvers_config_file,
         )
-        handle_dependencies: str = ""
-        if dependencies := get_dependencies(builder):
+        dependencies = get_dependencies(builder)
+        handle_dependencies = ""  # str
+        if dependencies:
             handle_dependencies = "\n".join(
                 tool_dependency_manager.dependency_shell_commands(
                     dependencies, job_directory=builder.tmpdir
diff --git a/cwltool/utils.py b/cwltool/utils.py
index 25d6c8873..58613e088 100644
--- a/cwltool/utils.py
+++ b/cwltool/utils.py
@@ -1,7 +1,6 @@
 """Shared functions and other definitions."""
 import collections
 import fcntl
-import importlib.metadata
 import os
 import random
 import shutil
@@ -28,17 +27,16 @@
     Generator,
     Iterable,
     List,
-    Literal,
     MutableMapping,
     MutableSequence,
     NamedTuple,
     Optional,
     Set,
     Tuple,
-    TypedDict,
     Union,
     cast,
 )
+from typing_extensions import Literal, TypedDict
 
 import requests
 from cachecontrol import CacheControl
@@ -47,6 +45,11 @@
 from schema_salad.exceptions import ValidationException
 from schema_salad.ref_resolver import Loader
 
+if sys.version_info >= (3, 8):
+    import importlib.metadata as importlib_metadata
+else:
+    import importlib_metadata
+
 if TYPE_CHECKING:
     from .command_line_tool import CallbackJob, ExpressionJob
     from .job import CommandLineJob, JobBase
@@ -117,7 +120,8 @@ class WorkflowStateItem(NamedTuple):
 
 def versionstring() -> str:
     """Version of CWLtool used to execute the workflow."""
-    if pkg := importlib.metadata.version("cwltool"):
+    pkg = importlib_metadata.version("cwltool")
+    if pkg:
         return f"{sys.argv[0]} {pkg}"
     return "{} {}".format(sys.argv[0], "unknown version")
 
diff --git a/docs/conf.py b/docs/conf.py
index fbc089caa..94c3e1e64 100644
--- a/docs/conf.py
+++ b/docs/conf.py
@@ -14,7 +14,6 @@
 import sys
 from datetime import datetime
 import time
-import importlib.metadata
 
 sys.path.insert(0, os.path.abspath(".."))
 
@@ -82,7 +81,12 @@
 # so a file named "default.css" will overwrite the builtin "default.css".
 html_static_path = ["_static"]
 
-release = importlib.metadata.version("cwltool")
+
+if sys.version_info >= (3, 8):
+    import importlib.metadata as importlib_metadata
+else:
+    import importlib_metadata
+release = importlib_metadata.version("cwltool")
 version = ".".join(release.split(".")[:2])
 
 autoapi_dirs = ["../cwltool"]
diff --git a/gittaggers.py b/gittaggers.py
index c25dbe1af..ab54b3e05 100644
--- a/gittaggers.py
+++ b/gittaggers.py
@@ -2,13 +2,16 @@
 import sys
 import time
 
-import importlib.metadata
+if sys.version_info >= (3, 8):
+    import importlib.metadata as importlib_metadata
+else:
+    import importlib_metadata
 
 from typing import Any
 
 from setuptools.command.egg_info import egg_info
 
-SETUPTOOLS_VER = importlib.metadata.version("setuptools").split(".")
+SETUPTOOLS_VER = importlib_metadata.version("setuptools").split(".")
 
 RECENT_SETUPTOOLS = (
     int(SETUPTOOLS_VER[0]) > 40
diff --git a/pyproject.toml b/pyproject.toml
index 70b985255..bbdd251ba 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -15,4 +15,4 @@ build-backend = "setuptools.build_meta"
 
 [tool.black]
 line-length = 100
-target-version = [ "py38" ]
+target-version = [ "py37" ]
diff --git a/requirements.txt b/requirements.txt
index d92936b34..34e8be3ad 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -7,7 +7,9 @@ schema-salad>=8.4.20230426093816,<9
 prov==1.5.1
 mypy-extensions
 psutil>=5.6.6
+typing-extensions
 importlib_resources>=1.4  # equivalent to Python 3.9
+importlib_metadata;python_version<'3.8'  # equivalent to Python 3.9
 coloredlogs
 pydot>=1.4.1
 argcomplete>=1.12.0
diff --git a/setup.py b/setup.py
index a86b1a4ad..7ecc43dbd 100644
--- a/setup.py
+++ b/setup.py
@@ -120,7 +120,9 @@
         "prov == 1.5.1",
         "mypy-extensions",
         "psutil >= 5.6.6",
+        "typing-extensions",
         "importlib_resources>=1.4",
+        "importlib_metadata;python_version<'3.8'",
         "coloredlogs",
         "pydot >= 1.4.1",
         "argcomplete",
@@ -130,7 +132,7 @@
     extras_require={
         "deps": ["galaxy-tool-util >= 22.1.2, <23", "galaxy-util <23"],
     },
-    python_requires=">=3.8, <4",
+    python_requires=">=3.7, <4",
     setup_requires=PYTEST_RUNNER,
     test_suite="tests",
     tests_require=[
@@ -156,6 +158,7 @@
         "Operating System :: POSIX",
         "Operating System :: POSIX :: Linux",
         "Programming Language :: Python :: 3",
+        "Programming Language :: Python :: 3.7",
         "Programming Language :: Python :: 3.8",
         "Programming Language :: Python :: 3.9",
         "Programming Language :: Python :: 3.10",
diff --git a/tox.ini b/tox.ini
index 86bc7c0aa..6033a1a03 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,7 +1,7 @@
 [tox]
 envlist =
   py3{8,9,10,11,12}-lint
-  py3{8,9,10,11,12}-unit
+  py3{7,8,9,10,11,12}-unit
   py3{8,9,10,11,12}-bandit
   py3{8,9,10,11,12}-mypy
   py311-lintreadme
@@ -16,6 +16,7 @@ testpaths = tests
 
 [gh-actions]
 python =
+  3.7: py37
   3.8: py38
   3.9: py39
   3.10: py310
@@ -24,10 +25,10 @@ python =
 
 [testenv]
 skipsdist =
-  py3{8,9,10,11,12}-!{unit,mypy,lintreadme} = True
+  py3{7,8,9,10,11,12}-!{unit,mypy,lintreadme} = True
 
 description =
-  py3{8,9,10,11,12}-unit: Run the unit tests
+  py3{7,8,9,10,11,12}-unit: Run the unit tests
   py3{8,9,10,11,12}-lint: Lint the Python code
   py3{8,9,10,11,12}-bandit: Search for common security issues
   py3{8,9,10,11,12}-mypy: Check for type safety
@@ -41,11 +42,11 @@ passenv =
   PROOT_NO_SECCOMP
 
 extras =
-  py3{8,9,10,11,12}-unit: deps
+  py3{7,8,9,10,11,12}-unit: deps
 
 deps =
-  py3{8,9,10,11,12}-{unit,lint,bandit,mypy}: -rrequirements.txt
-  py3{8,9,10,11,12}-{unit,mypy}: -rtest-requirements.txt
+  py3{7,8,9,10,11,12}-{unit,lint,bandit,mypy}: -rrequirements.txt
+  py3{7,8,9,10,11,12}-{unit,mypy}: -rtest-requirements.txt
   py3{8,9,10,11,12}-lint: -rlint-requirements.txt
   py3{8,9,10,11,12}-bandit: bandit
   py3{8,9,10,11,12}-bandit: importlib_metadata != 4.8.0
@@ -57,14 +58,14 @@ deps =
   py311-lintreadme: readme_renderer[rst]
 
 setenv =
-  py3{8,9,10,11,12}-unit: LC_ALL = C.UTF-8
+  py3{7,8,9,10,11,12}-unit: LC_ALL = C.UTF-8
 
 commands_pre =
-  py3{8,9,10,11,12}-unit: python -m pip install -U pip setuptools wheel
+  py3{7,8,9,10,11,12}-unit: python -m pip install -U pip setuptools wheel
   py311-lintreadme: python -m build --outdir {distdir}
 
 commands =
-  py3{8,9,10,11,12}-unit: make coverage-report coverage.xml PYTEST_EXTRA={posargs}
+  py3{7,8,9,10,11,12}-unit: make coverage-report coverage.xml PYTEST_EXTRA={posargs}
   py3{8,9,10,11,12}-bandit: bandit -r cwltool
   py3{8,9,10,11,12}-lint: make flake8 format-check codespell-check
   py3{8,9,10,11,12}-mypy: make mypy PYTEST_EXTRA={posargs}
@@ -74,6 +75,6 @@ commands =
   py311-lintreadme: twine check {distdir}/*
 
 skip_install =
-  py3{8,9,10,11,12}-{bandit,lint,mypy,shellcheck,pydocstyle,lintreadme}: true
+  py3{7,8,9,10,11,12}-{bandit,lint,mypy,shellcheck,pydocstyle,lintreadme}: true
 
 allowlist_externals = make