diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6360dd742..581fc07b4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,7 @@ SPDX-License-Identifier: GPL-3.0-or-later
 
 ### Changed
 
+- **breaking:** core: fix integer overflow and return "unsigned long" in function util_version_number
 - core: write configuration files on disk only if there are changes ([#2250](https://github.com/weechat/weechat/issues/2250))
 
 ### Added
diff --git a/doc/en/weechat_plugin_api.en.adoc b/doc/en/weechat_plugin_api.en.adoc
index f4a69c085..88539a2ea 100644
--- a/doc/en/weechat_plugin_api.en.adoc
+++ b/doc/en/weechat_plugin_api.en.adoc
@@ -4879,7 +4879,7 @@ This function is not available in scripting API.
 
 ==== util_version_number
 
-_WeeChat ≥ 0.3.9._
+_WeeChat ≥ 0.3.9, updated in 4.7.0._
 
 Convert a string with WeeChat version to a number.
 
@@ -4887,7 +4887,7 @@ Prototype:
 
 [source,c]
 ----
-int weechat_util_version_number (const char *version);
+unsigned long weechat_util_version_number (const char *version);
 ----
 
 Arguments:
diff --git a/doc/fr/weechat_plugin_api.fr.adoc b/doc/fr/weechat_plugin_api.fr.adoc
index f866def55..4eed9d52c 100644
--- a/doc/fr/weechat_plugin_api.fr.adoc
+++ b/doc/fr/weechat_plugin_api.fr.adoc
@@ -4960,7 +4960,7 @@ Cette fonction n'est pas disponible dans l'API script.
 
 ==== util_version_number
 
-_WeeChat ≥ 0.3.9._
+_WeeChat ≥ 0.3.9, mis à jour dans la 4.7.0._
 
 Convertir une chaîne avec la version WeeChat en nombre.
 
@@ -4968,7 +4968,7 @@ Prototype :
 
 [source,c]
 ----
-int weechat_util_version_number (const char *version);
+unsigned long weechat_util_version_number (const char *version);
 ----
 
 Paramètres :
diff --git a/doc/it/weechat_plugin_api.it.adoc b/doc/it/weechat_plugin_api.it.adoc
index 00ac420ea..d25dc9167 100644
--- a/doc/it/weechat_plugin_api.it.adoc
+++ b/doc/it/weechat_plugin_api.it.adoc
@@ -5100,7 +5100,8 @@ Questa funzione non è disponibile nelle API per lo scripting.
 
 ==== util_version_number
 
-_WeeChat ≥ 0.3.9._
+// TRANSLATION MISSING
+_WeeChat ≥ 0.3.9, updated in 4.7.0._
 
 // TRANSLATION MISSING
 Convert a string with WeeChat version to a number.
@@ -5109,7 +5110,7 @@ Prototipo:
 
 [source,c]
 ----
-int weechat_util_version_number (const char *version);
+unsigned long weechat_util_version_number (const char *version);
 ----
 
 Argomenti:
diff --git a/doc/ja/weechat_plugin_api.ja.adoc b/doc/ja/weechat_plugin_api.ja.adoc
index 154829bce..86f2c1650 100644
--- a/doc/ja/weechat_plugin_api.ja.adoc
+++ b/doc/ja/weechat_plugin_api.ja.adoc
@@ -5014,7 +5014,8 @@ weechat_util_parse_time ("2023-12-25T10:29:09.456789Z", &tv);  /* == 1 */
 
 ==== util_version_number
 
-_WeeChat バージョン 0.3.9 以上で利用可。_
+// TRANSLATION MISSING
+_WeeChat ≥ 0.3.9, updated in 4.7.0._
 
 WeeChat バージョンの文字列を番号に変換。
 
@@ -5022,7 +5023,7 @@ WeeChat バージョンの文字列を番号に変換。
 
 [source,c]
 ----
-int weechat_util_version_number (const char *version);
+unsigned long weechat_util_version_number (const char *version);
 ----
 
 引数:
diff --git a/doc/sr/weechat_plugin_api.sr.adoc b/doc/sr/weechat_plugin_api.sr.adoc
index b6fcabd45..12fd16720 100644
--- a/doc/sr/weechat_plugin_api.sr.adoc
+++ b/doc/sr/weechat_plugin_api.sr.adoc
@@ -4739,7 +4739,7 @@ weechat_util_parse_time ("2023-12-25T10:29:09.456789Z", &tv);  /* == 1 */
 
 ==== util_version_number
 
-_WeeChat ≥ 0.3.9._
+_WeeChat ≥ 0.3.9, ажурирано у верзији 4.7.0._
 
 Конвертује стринг са верзијом програма WeeChat у број.
 
@@ -4747,7 +4747,7 @@ _WeeChat ≥ 0.3.9._
 
 [source,c]
 ----
-int weechat_util_version_number (const char *version);
+unsigned long weechat_util_version_number (const char *version);
 ----
 
 Аргументи:
diff --git a/src/core/core-util.c b/src/core/core-util.c
index 93d88a768..2a3d426df 100644
--- a/src/core/core-util.c
+++ b/src/core/core-util.c
@@ -629,13 +629,13 @@ util_parse_delay (const char *string_delay, unsigned long long default_factor,
  *   "0.3.0"     ==> 196608   (== 0x00030000)
  */
 
-int
+unsigned long
 util_version_number (const char *version)
 {
     char **items, buf[64], *error;
     const char *ptr_item;
-    int num_items, i, version_int[4], index_buf;
-    long number;
+    int num_items, i, index_buf;
+    unsigned long number, values[4];
 
     if (!version || !version[0])
         return 0;
@@ -647,7 +647,7 @@ util_version_number (const char *version)
                           4, &num_items);
     for (i = 0; i < 4; i++)
     {
-        version_int[i] = 0;
+        values[i] = 0;
         if (items && (i < num_items))
         {
             ptr_item = items[i];
@@ -667,20 +667,18 @@ util_version_number (const char *version)
             if (buf[0])
             {
                 error = NULL;
-                number = strtol (buf, &error, 10);
+                number = strtoul (buf, &error, 10);
                 if (error && !error[0])
                 {
-                    if (number < 0)
-                        number = 0;
-                    else if (number > 0xFF)
+                    if (number > 0xFF)
                         number = 0xFF;
-                    version_int[i] = number;
+                    values[i] = number;
                 }
             }
         }
     }
     string_free_split (items);
 
-    return (version_int[0] << 24) | (version_int[1] << 16)
-        | (version_int[2] << 8) | version_int[3];
+    return (values[0] << 24) | (values[1] << 16)
+        | (values[2] << 8) | values[3];
 }
diff --git a/src/core/core-util.h b/src/core/core-util.h
index 620ae6575..0bad20765 100644
--- a/src/core/core-util.h
+++ b/src/core/core-util.h
@@ -48,6 +48,6 @@ extern int util_parse_delay (const char *string_delay,
                              unsigned long long *delay);
 
 /* version */
-extern int util_version_number (const char *version);
+extern unsigned long util_version_number (const char *version);
 
 #endif /* WEECHAT_UTIL_H */
diff --git a/src/plugins/plugin-api-info.c b/src/plugins/plugin-api-info.c
index 48e3660ea..c3dd0883c 100644
--- a/src/plugins/plugin-api-info.c
+++ b/src/plugins/plugin-api-info.c
@@ -102,7 +102,7 @@ plugin_api_info_version_number_cb (const void *pointer, void *data,
     (void) arguments;
 
     snprintf (
-        version_number, sizeof (version_number), "%d",
+        version_number, sizeof (version_number), "%lu",
         util_version_number (
             (arguments && arguments[0]) ? arguments : version_get_version ()));
     return strdup (version_number);
diff --git a/src/plugins/script/script-repo.c b/src/plugins/script/script-repo.c
index 1903f59c2..64777fc7e 100644
--- a/src/plugins/script/script-repo.c
+++ b/src/plugins/script/script-repo.c
@@ -1109,7 +1109,8 @@ script_repo_file_read (int quiet)
     const char *ptr_desc;
     gzFile file;
     struct t_script_repo *script;
-    int version_number, version_ok, script_ok;
+    unsigned long version_number;
+    int version_ok, script_ok;
     struct tm tm_script;
     struct t_hashtable *descriptions;
 
diff --git a/src/plugins/weechat-plugin.h b/src/plugins/weechat-plugin.h
index edb11f888..576fc1774 100644
--- a/src/plugins/weechat-plugin.h
+++ b/src/plugins/weechat-plugin.h
@@ -76,7 +76,7 @@ struct t_weelist_item;
  * please change the date with current one; for a second change at same
  * date, increment the 01, otherwise please keep 01.
  */
-#define WEECHAT_PLUGIN_API_VERSION "20250507-01"
+#define WEECHAT_PLUGIN_API_VERSION "20250508-01"
 
 /* macros for defining plugin infos */
 #define WEECHAT_PLUGIN_NAME(__name)                                     \
@@ -467,7 +467,7 @@ struct t_weechat_plugin
     int (*util_strftimeval) (char *string, int max, const char *format,
                              struct timeval *tv);
     int (*util_parse_time) (const char *datetime, struct timeval *tv);
-    int (*util_version_number) (const char *version);
+    unsigned long (*util_version_number) (const char *version);
 
     /* sorted lists */
     struct t_weelist *(*list_new) (void);
diff --git a/tests/unit/core/test-core-util.cpp b/tests/unit/core/test-core-util.cpp
index f17f14cef..155f7834d 100644
--- a/tests/unit/core/test-core-util.cpp
+++ b/tests/unit/core/test-core-util.cpp
@@ -520,23 +520,25 @@ TEST(CoreUtil, ParseDelay)
 
 TEST(CoreUtil, VersionNumber)
 {
-    LONGS_EQUAL(0, util_version_number (NULL));
-    LONGS_EQUAL(0, util_version_number (""));
-    LONGS_EQUAL(0, util_version_number ("abc"));
+    CHECK(util_version_number (NULL) == 0);
+    CHECK(util_version_number ("") == 0);
+    CHECK(util_version_number ("abc") == 0);
 
-    LONGS_EQUAL(0x00030200, util_version_number ("0.3.2-dev"));
-    LONGS_EQUAL(0x00030200, util_version_number ("0.3.2-rc1"));
-    LONGS_EQUAL(0x00030200, util_version_number ("0.3.2"));
-    LONGS_EQUAL(0x00030101, util_version_number ("0.3.1.1"));
-    LONGS_EQUAL(0x00030100, util_version_number ("0.3.1"));
-    LONGS_EQUAL(0x00030000, util_version_number ("0.3.0"));
-    LONGS_EQUAL(0x01000000, util_version_number ("1.0"));
-    LONGS_EQUAL(0x01000000, util_version_number ("1.0.0"));
-    LONGS_EQUAL(0x01000000, util_version_number ("1.0.0.0"));
-    LONGS_EQUAL(0x01000100, util_version_number ("1.0.1"));
-    LONGS_EQUAL(0x01000200, util_version_number ("1.0.2"));
-    LONGS_EQUAL(0x01010000, util_version_number ("1.1"));
-    LONGS_EQUAL(0x01010100, util_version_number ("1.1.1"));
-    LONGS_EQUAL(0x01010200, util_version_number ("1.1.2"));
-    LONGS_EQUAL(0x01020304, util_version_number ("1.2.3.4"));
+    CHECK(util_version_number ("0.3.2-dev") == 0x00030200);
+    CHECK(util_version_number ("0.3.2-rc1") == 0x00030200);
+    CHECK(util_version_number ("0.3.2") == 0x00030200);
+    CHECK(util_version_number ("0.3.1.1") == 0x00030101);
+    CHECK(util_version_number ("0.3.1") == 0x00030100);
+    CHECK(util_version_number ("0.3.0") == 0x00030000);
+    CHECK(util_version_number ("1.0") == 0x01000000);
+    CHECK(util_version_number ("1.0.0") == 0x01000000);
+    CHECK(util_version_number ("1.0.0.0") == 0x01000000);
+    CHECK(util_version_number ("1.0.1") == 0x01000100);
+    CHECK(util_version_number ("1.0.2") == 0x01000200);
+    CHECK(util_version_number ("1.1") == 0x01010000);
+    CHECK(util_version_number ("1.1.1") == 0x01010100);
+    CHECK(util_version_number ("1.1.2") == 0x01010200);
+    CHECK(util_version_number ("1.2.3.4") == 0x01020304);
+    CHECK(util_version_number ("255.255.255.255") == 0xFFFFFFFF);
+    CHECK(util_version_number ("999999999.999999999.999999999.999999999") == 0xFFFFFFFF);
 }
diff --git a/tests/unit/plugins/test-plugin-api-info.cpp b/tests/unit/plugins/test-plugin-api-info.cpp
index e5979dc7b..e4b2abea2 100644
--- a/tests/unit/plugins/test-plugin-api-info.cpp
+++ b/tests/unit/plugins/test-plugin-api-info.cpp
@@ -83,7 +83,7 @@ TEST(PluginApiInfo, VersionNumberCb)
     char *str, str_version_number[128];
 
     snprintf (str_version_number, sizeof (str_version_number),
-              "%d", util_version_number (version_get_version ()));
+              "%lu", util_version_number (version_get_version ()));
     WEE_TEST_STR(str_version_number, hook_info_get (NULL, "version_number", NULL));
     WEE_TEST_STR(str_version_number, hook_info_get (NULL, "version_number", ""));