diff --git a/system/HTTP/CURLRequest.php b/system/HTTP/CURLRequest.php
index 4b1c9c625399..9da231c17716 100644
--- a/system/HTTP/CURLRequest.php
+++ b/system/HTTP/CURLRequest.php
@@ -651,11 +651,12 @@ protected function setCURLOptions(array $curlOptions = [], array $config = [])
 
         // version
         if (! empty($config['version'])) {
-            if ($config['version'] === 1.0) {
+            $version = sprintf('%.1F', $config['version']);
+            if ($version === '1.0') {
                 $curlOptions[CURLOPT_HTTP_VERSION] = CURL_HTTP_VERSION_1_0;
-            } elseif ($config['version'] === 1.1) {
+            } elseif ($version === '1.1') {
                 $curlOptions[CURLOPT_HTTP_VERSION] = CURL_HTTP_VERSION_1_1;
-            } elseif ($config['version'] === 2.0) {
+            } elseif ($version === '2.0') {
                 $curlOptions[CURLOPT_HTTP_VERSION] = CURL_HTTP_VERSION_2_0;
             }
         }
diff --git a/tests/system/HTTP/CURLRequestTest.php b/tests/system/HTTP/CURLRequestTest.php
index dc48eb621d80..f14198be2264 100644
--- a/tests/system/HTTP/CURLRequestTest.php
+++ b/tests/system/HTTP/CURLRequestTest.php
@@ -1227,4 +1227,34 @@ public function testGetHeaderLineContentType(): void
 
         $this->assertSame('text/html; charset=UTF-8', $response->getHeaderLine('Content-Type'));
     }
+
+    public function testHTTPversionAsString(): void
+    {
+        $this->request->request('POST', '/post', [
+            'version' => '1.0',
+        ]);
+
+        $options = $this->request->curl_options;
+
+        $this->assertArrayHasKey(CURLOPT_HTTP_VERSION, $options);
+        $this->assertSame(CURL_HTTP_VERSION_1_0, $options[CURLOPT_HTTP_VERSION]);
+
+        $this->request->request('POST', '/post', [
+            'version' => '1.1',
+        ]);
+
+        $options = $this->request->curl_options;
+
+        $this->assertArrayHasKey(CURLOPT_HTTP_VERSION, $options);
+        $this->assertSame(CURL_HTTP_VERSION_1_1, $options[CURLOPT_HTTP_VERSION]);
+
+        $this->request->request('POST', '/post', [
+            'version' => '2.0',
+        ]);
+
+        $options = $this->request->curl_options;
+
+        $this->assertArrayHasKey(CURLOPT_HTTP_VERSION, $options);
+        $this->assertSame(CURL_HTTP_VERSION_2_0, $options[CURLOPT_HTTP_VERSION]);
+    }
 }
diff --git a/user_guide_src/source/changelogs/v4.5.4.rst b/user_guide_src/source/changelogs/v4.5.4.rst
index bf737a99a335..51a9fd74f407 100644
--- a/user_guide_src/source/changelogs/v4.5.4.rst
+++ b/user_guide_src/source/changelogs/v4.5.4.rst
@@ -30,6 +30,9 @@ Deprecations
 Bugs Fixed
 **********
 
+- **CURLRequest:** Fixed a bug preventing the use of strings for ``version`` in the config array
+  when making requests.
+
 See the repo's
 `CHANGELOG.md <https://github.com/codeigniter4/CodeIgniter4/blob/develop/CHANGELOG.md>`_
 for a complete list of bugs fixed.