diff --git a/core/config.class.inc.php b/core/config.class.inc.php
index 4f6b67e2f..6220a53e6 100644
--- a/core/config.class.inc.php
+++ b/core/config.class.inc.php
@@ -1456,14 +1456,6 @@ class Config
 			'source_of_value' => '',
 			'show_in_conf_sample' => false,
 		],
-		'use_legacy_dbsearch' => [
-			'type' => 'bool',
-			'description' => 'If set, DBSearch will use legacy SQL query generation',
-			'default' => false,
-			'value' => false,
-			'source_of_value' => '',
-			'show_in_conf_sample' => false,
-		],
 		'query_cache_enabled' => [
 			'type' => 'bool',
 			'description' => 'If set, DBSearch will use cache for query generation',
diff --git a/core/dbsearch.class.php b/core/dbsearch.class.php
index 849f2a56f..4ab981b22 100644
--- a/core/dbsearch.class.php
+++ b/core/dbsearch.class.php
@@ -16,24 +16,10 @@
  *
  * You should have received a copy of the GNU Affero General Public License
  */
-
-
-$bUseLegacyDBSearch = utils::GetConfig()->Get('use_legacy_dbsearch');
-
-if ($bUseLegacyDBSearch)
-{
-	// excluded from autoload
-	require_once (APPROOT.'core/legacy/querybuilderexpressionslegacy.class.inc.php');
-	require_once (APPROOT.'core/legacy/querybuildercontextlegacy.class.inc.php');
-	require_once(APPROOT.'core/legacy/dbobjectsearchlegacy.class.php');
-}
-else
-{
 	// excluded from autoload
 	require_once (APPROOT.'core/querybuilderexpressions.class.inc.php');
 	require_once (APPROOT.'core/querybuildercontext.class.inc.php');
 	require_once(APPROOT.'core/dbobjectsearch.class.php');
-}
 
 /**
  * An object search
diff --git a/core/legacy/dbobjectsearchlegacy.class.php b/core/legacy/dbobjectsearchlegacy.class.php
index 6965a82e9..a858d24d4 100644
--- a/core/legacy/dbobjectsearchlegacy.class.php
+++ b/core/legacy/dbobjectsearchlegacy.class.php
@@ -17,7 +17,9 @@
 //   along with iTop. If not, see <http://www.gnu.org/licenses/>
 //
 
-// THIS FILE IS DEPRECATED
+/*
+* @deprecated 3.0.0 N°3141 - Deprecate legacy SQL build
+*/
 
 /** @internal Dev hack for disabling some query build optimizations (Folding/Merging) */
 define('ENABLE_OPT', true);
diff --git a/core/legacy/querybuildercontextlegacy.class.inc.php b/core/legacy/querybuildercontextlegacy.class.inc.php
index 8af0fc3d1..a3c60ee65 100644
--- a/core/legacy/querybuildercontextlegacy.class.inc.php
+++ b/core/legacy/querybuildercontextlegacy.class.inc.php
@@ -17,6 +17,7 @@
 //   along with iTop. If not, see <http://www.gnu.org/licenses/>
 
 /**
+ * @deprecated 3.1.0 N°3141 - Deprecate legacy SQL build
  * Associated with the metamodel -> MakeQuery/MakeQuerySingleTable
  *
  * @copyright   Copyright (C) 2010-2021 Combodo SARL
diff --git a/core/legacy/querybuilderexpressionslegacy.class.inc.php b/core/legacy/querybuilderexpressionslegacy.class.inc.php
index 2bd5d911c..c5026c914 100644
--- a/core/legacy/querybuilderexpressionslegacy.class.inc.php
+++ b/core/legacy/querybuilderexpressionslegacy.class.inc.php
@@ -1,5 +1,7 @@
 <?php
-
+/*
+ * @deprecated 3.1.0 N°3141 - Deprecate legacy SQL build
+ */
 class QueryBuilderExpressions
 {
 	/**
diff --git a/datamodels/2.x/itop-hub-connector/ajax.php b/datamodels/2.x/itop-hub-connector/ajax.php
index 60df89705..0ea3145f1 100644
--- a/datamodels/2.x/itop-hub-connector/ajax.php
+++ b/datamodels/2.x/itop-hub-connector/ajax.php
@@ -22,10 +22,12 @@
  * @copyright Copyright (C) 2010-2021 Combodo SARL
  * @license http://opensource.org/licenses/AGPL-3.0
  */
-if (!defined('__DIR__')) define('__DIR__', dirname(__FILE__));
-require_once (APPROOT.'application/webpage.class.inc.php');
-require_once (APPROOT.'application/utils.inc.php');
-require_once (APPROOT.'core/log.class.inc.php');
+if (!defined('__DIR__')) {
+	define('__DIR__', dirname(__FILE__));
+}
+
+require_once(APPROOT.'application/utils.inc.php');
+require_once(APPROOT.'core/log.class.inc.php');
 IssueLog::Enable(APPROOT.'log/error.log');
 
 require_once(APPROOT.'setup/runtimeenv.class.inc.php');
diff --git a/pages/run_query.php b/pages/run_query.php
index e930ceeb6..19b294507 100644
--- a/pages/run_query.php
+++ b/pages/run_query.php
@@ -265,7 +265,7 @@ EOF
 
 		$aOrderBy = MetaModel::GetOrderByDefault($sMainClass);
 
-		if (($oFilter instanceof DBObjectSearch) && !MetaModel::GetConfig()->Get('use_legacy_dbsearch')) {
+		if (($oFilter instanceof DBObjectSearch)) {
 			// OQL Developed for Count
 			$oSQLObjectQueryBuilder = new SQLObjectQueryBuilder($oFilter);
 			$oBuild = new QueryBuilderContext($oFilter, $aModifierProperties, null, null, null, $aCountAttToLoad);
@@ -280,7 +280,7 @@ EOF
 		$oCountResultQuerySet->AddSubBlock(UIContentBlockUIBlockFactory::MakeForCode($sSQL));
 		$aMoreInfoBlocks[] = $oCountResultQuerySet;
 
-		if (($oFilter instanceof DBObjectSearch) && !MetaModel::GetConfig()->Get('use_legacy_dbsearch')) {
+		if (($oFilter instanceof DBObjectSearch)) {
 			// OQL Developed
 			$oSQLObjectQueryBuilder = new SQLObjectQueryBuilder($oFilter);
 			$oBuild = new QueryBuilderContext($oFilter, $aModifierProperties);