diff --git a/.github/workflows/check-and-publish.yml b/.github/workflows/check-and-publish.yml
index 0184526..5af80f8 100644
--- a/.github/workflows/check-and-publish.yml
+++ b/.github/workflows/check-and-publish.yml
@@ -35,7 +35,7 @@ jobs:
       fail-fast: false
       matrix:
         platform: [windows-latest, ubuntu-latest, macos-latest]
-        python-version: ["3.7", "3.8", "3.9", "3.10", "3.11"]
+        python-version: ["3.8", "3.9", "3.10", "3.11", "3.12"]
 
     name: Python ${{ matrix.python-version }} on ${{ matrix.platform }}
     runs-on: ${{ matrix.platform }}
diff --git a/cdsapi/api.py b/cdsapi/api.py
index 509f579..9b47e55 100644
--- a/cdsapi/api.py
+++ b/cdsapi/api.py
@@ -45,6 +45,35 @@ def read_config(path):
     return config
 
 
+def get_url_key_verify(url, key, verify):
+    if url is None:
+        url = os.environ.get("CDSAPI_URL")
+    if key is None:
+        key = os.environ.get("CDSAPI_KEY")
+    dotrc = os.environ.get("CDSAPI_RC", os.path.expanduser("~/.cdsapirc"))
+
+    if url is None or key is None:
+        if os.path.exists(dotrc):
+            config = read_config(dotrc)
+
+            if key is None:
+                key = config.get("key")
+
+            if url is None:
+                url = config.get("url")
+
+            if verify is None:
+                verify = bool(int(config.get("verify", 1)))
+
+    if url is None or key is None or key is None:
+        raise Exception("Missing/incomplete configuration file: %s" % (dotrc))
+
+    # If verify is still None, then we set to default value of True
+    if verify is None:
+        verify = True
+    return url, key, verify
+
+
 def toJSON(obj):
     to_json = getattr(obj, "toJSON", None)
     if callable(to_json):
@@ -248,6 +277,14 @@ def __del__(self):
 class Client(object):
     logger = logging.getLogger("cdsapi")
 
+    def __new__(cls, url=None, key=None, *args, **kwargs):
+        _, token, _ = get_url_key_verify(url, key, None)
+        if ":" in token:
+            return super().__new__(cls)
+        import cads_api_client.legacy_api_client
+
+        return super().__new__(cads_api_client.legacy_api_client.LegacyApiClient)
+
     def __init__(
         self,
         url=None,
@@ -285,31 +322,7 @@ def __init__(
                 handler.setFormatter(formatter)
                 self.logger.addHandler(handler)
 
-        if url is None:
-            url = os.environ.get("CDSAPI_URL")
-        if key is None:
-            key = os.environ.get("CDSAPI_KEY")
-        dotrc = os.environ.get("CDSAPI_RC", os.path.expanduser("~/.cdsapirc"))
-
-        if url is None or key is None:
-            if os.path.exists(dotrc):
-                config = read_config(dotrc)
-
-                if key is None:
-                    key = config.get("key")
-
-                if url is None:
-                    url = config.get("url")
-
-                if verify is None:
-                    verify = bool(int(config.get("verify", 1)))
-
-        if url is None or key is None or key is None:
-            raise Exception("Missing/incomplete configuration file: %s" % (dotrc))
-
-        # If verify is still None, then we set to default value of True
-        if verify is None:
-            verify = True
+        url, key, verify = get_url_key_verify(url, key, verify)
 
         self.url = url
         self.key = key
diff --git a/setup.py b/setup.py
index 1692456..3a79127 100644
--- a/setup.py
+++ b/setup.py
@@ -45,6 +45,7 @@ def read(fname):
     packages=setuptools.find_packages(),
     include_package_data=True,
     install_requires=[
+        "cads-api-client>=0.9.2",
         "requests>=2.5.0",
         "tqdm",
     ],
@@ -54,11 +55,11 @@ def read(fname):
         "Intended Audience :: Developers",
         "Programming Language :: Python",
         "Programming Language :: Python :: 3",
-        "Programming Language :: Python :: 3.7",
         "Programming Language :: Python :: 3.8",
         "Programming Language :: Python :: 3.9",
         "Programming Language :: Python :: 3.10",
         "Programming Language :: Python :: 3.11",
+        "Programming Language :: Python :: 3.12",
         "Programming Language :: Python :: Implementation :: CPython",
         "Programming Language :: Python :: Implementation :: PyPy",
         "Operating System :: OS Independent",
diff --git a/tests/test_api.py b/tests/test_api.py
index 3725f1f..f037889 100644
--- a/tests/test_api.py
+++ b/tests/test_api.py
@@ -1,5 +1,8 @@
 import os
 
+import cads_api_client.legacy_api_client
+import pytest
+
 import cdsapi
 
 
@@ -19,3 +22,28 @@ def test_request():
     r.download("test.grib")
 
     assert os.path.getsize("test.grib") == 2076600
+
+
+@pytest.mark.parametrize(
+    "key,expected_client",
+    [
+        (
+            ":",
+            cdsapi.Client,
+        ),
+        (
+            "",
+            cads_api_client.legacy_api_client.LegacyApiClient,
+        ),
+    ],
+)
+@pytest.mark.parametrize("key_from_env", [True, False])
+def test_instantiation(monkeypatch, key, expected_client, key_from_env):
+    if key_from_env:
+        monkeypatch.setenv("CDSAPI_KEY", key)
+        c = cdsapi.Client()
+    else:
+        c = cdsapi.Client(key=key)
+    assert isinstance(c, cdsapi.Client)
+    assert isinstance(c, expected_client)
+    assert c.key == key
diff --git a/tox.ini b/tox.ini
index d97570f..ee8bfcc 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-envlist = qc, py311, py310, py39, py38, py37, pypy3, pypy, deps
+envlist = qc, py312, py311, py310, py39, py38, pypy3, pypy, deps
 
 [testenv]
 setenv = PYTHONPATH = {toxinidir}
@@ -21,4 +21,4 @@ line_length=120
 [isort]
 profile=black
 [flake8]
-max-line-length = 120
\ No newline at end of file
+max-line-length = 120