diff --git a/htdocs/comm/propal/card.php b/htdocs/comm/propal/card.php
index 53ba07ba441..388a4f97d4b 100644
--- a/htdocs/comm/propal/card.php
+++ b/htdocs/comm/propal/card.php
@@ -722,7 +722,7 @@ if (empty($reshook)) {
 						$ret = $deposit->fetch($deposit->id); // Reload to get new records
 						$outputlangs = $langs;
 
-						if ($conf->global->MAIN_MULTILANGS) {
+						if (!empty($conf->global->MAIN_MULTILANGS)) {
 							$outputlangs = new Translate('', $conf);
 							$outputlangs->setDefaultLang($deposit->thirdparty->default_lang);
 							$outputlangs->load('products');
diff --git a/htdocs/core/modules/propale/doc/pdf_azur.modules.php b/htdocs/core/modules/propale/doc/pdf_azur.modules.php
index 86d6306a576..c2971c9344e 100644
--- a/htdocs/core/modules/propale/doc/pdf_azur.modules.php
+++ b/htdocs/core/modules/propale/doc/pdf_azur.modules.php
@@ -793,7 +793,7 @@ class pdf_azur extends ModelePDFPropales
 							// Find the desire PDF
 							$filetomerge = new Propalmergepdfproduct($this->db);
 
-							if ($conf->global->MAIN_MULTILANGS) {
+							if (!empty($conf->global->MAIN_MULTILANGS)) {
 								$filetomerge->fetch_by_product($line->fk_product, $outputlangs->defaultlang);
 							} else {
 								$filetomerge->fetch_by_product($line->fk_product);
diff --git a/htdocs/core/modules/propale/doc/pdf_cyan.modules.php b/htdocs/core/modules/propale/doc/pdf_cyan.modules.php
index ec04a8e8906..9d52132db56 100644
--- a/htdocs/core/modules/propale/doc/pdf_cyan.modules.php
+++ b/htdocs/core/modules/propale/doc/pdf_cyan.modules.php
@@ -918,7 +918,7 @@ class pdf_cyan extends ModelePDFPropales
 							// Find the desire PDF
 							$filetomerge = new Propalmergepdfproduct($this->db);
 
-							if ($conf->global->MAIN_MULTILANGS) {
+							if (!empty($conf->global->MAIN_MULTILANGS)) {
 								$filetomerge->fetch_by_product($line->fk_product, $outputlangs->defaultlang);
 							} else {
 								$filetomerge->fetch_by_product($line->fk_product);
diff --git a/htdocs/datapolicy/admin/setupmail.php b/htdocs/datapolicy/admin/setupmail.php
index e2f562ee79b..825bd13b142 100644
--- a/htdocs/datapolicy/admin/setupmail.php
+++ b/htdocs/datapolicy/admin/setupmail.php
@@ -106,7 +106,7 @@ print '<form method="post" action="'.$_SERVER["PHP_SELF"].'?l='.$l.'">';
 print '<input type="hidden" name="token" value="'.newToken().'">';
 print '<input type="hidden" name="action" value="setvalue">';
 print '<table>';
-if ($conf->global->MAIN_MULTILANGS) {
+if (!empty($conf->global->MAIN_MULTILANGS)) {
 	print '<tr><td>'.$form->editfieldkey('DefaultLang', 'default_lang', '', null, 0).'</td><td colspan="3" class="maxwidthonsmartphone">'."\n";
 	print $formadmin->select_language((GETPOST('l') ? GETPOST('l') : $langs->defaultlang), 'default_lang', 0, 0, 1, 0, 0, 'maxwidth200onsmartphone');
 	print '</tr>';
diff --git a/htdocs/product/class/propalmergepdfproduct.class.php b/htdocs/product/class/propalmergepdfproduct.class.php
index e69c75c7336..b4b85c3852a 100644
--- a/htdocs/product/class/propalmergepdfproduct.class.php
+++ b/htdocs/product/class/propalmergepdfproduct.class.php
@@ -107,7 +107,7 @@ class Propalmergepdfproduct extends CommonObject
 		$sql = "INSERT INTO ".$this->db->prefix()."propal_merge_pdf_product(";
 		$sql .= "fk_product,";
 		$sql .= "file_name,";
-		if ($conf->global->MAIN_MULTILANGS) {
+		if (!empty($conf->global->MAIN_MULTILANGS)) {
 			$sql .= "lang,";
 		}
 		$sql .= "fk_user_author,";
@@ -116,7 +116,7 @@ class Propalmergepdfproduct extends CommonObject
 		$sql .= ") VALUES (";
 		$sql .= " ".(!isset($this->fk_product) ? 'NULL' : ((int) $this->fk_product)).",";
 		$sql .= " ".(!isset($this->file_name) ? 'NULL' : "'".$this->db->escape($this->file_name)."'").",";
-		if ($conf->global->MAIN_MULTILANGS) {
+		if (!empty($conf->global->MAIN_MULTILANGS)) {
 			$sql .= " ".(!isset($this->lang) ? 'NULL' : "'".$this->db->escape($this->lang)."'").",";
 		}
 		$sql .= " ".((int) $user->id).",";
@@ -186,7 +186,7 @@ class Propalmergepdfproduct extends CommonObject
 
 				$this->fk_product = $obj->fk_product;
 				$this->file_name = $obj->file_name;
-				if ($conf->global->MAIN_MULTILANGS) {
+				if (!empty($conf->global->MAIN_MULTILANGS)) {
 					$this->lang = $obj->lang;
 				}
 				$this->fk_user_author = $obj->fk_user_author;
@@ -311,7 +311,7 @@ class Propalmergepdfproduct extends CommonObject
 
 		$sql .= " fk_product=".(isset($this->fk_product) ? $this->fk_product : "null").",";
 		$sql .= " file_name=".(isset($this->file_name) ? "'".$this->db->escape($this->file_name)."'" : "null").",";
-		if ($conf->global->MAIN_MULTILANGS) {
+		if (!empty($conf->global->MAIN_MULTILANGS)) {
 			$sql .= " lang=".(isset($this->lang) ? "'".$this->db->escape($this->lang)."'" : "null").",";
 		}
 		$sql .= " fk_user_mod=".$user->id;
diff --git a/htdocs/product/document.php b/htdocs/product/document.php
index 2aaa2356879..ee5ba79a284 100644
--- a/htdocs/product/document.php
+++ b/htdocs/product/document.php
@@ -154,14 +154,14 @@ if ($action == 'filemerge' && $permissiontoadd) {
 
 		$filetomerge_file_array = GETPOST('filetoadd');
 
-		if ($conf->global->MAIN_MULTILANGS) {
+		if (!empty($conf->global->MAIN_MULTILANGS)) {
 			$lang_id = GETPOST('lang_id', 'aZ09');
 		}
 
 		// Delete all file already associated
 		$filetomerge = new Propalmergepdfproduct($db);
 
-		if ($conf->global->MAIN_MULTILANGS) {
+		if (!empty($conf->global->MAIN_MULTILANGS)) {
 			$result = $filetomerge->delete_by_product($user, $object->id, $lang_id);
 		} else {
 			$result = $filetomerge->delete_by_product($user, $object->id);
@@ -176,7 +176,7 @@ if ($action == 'filemerge' && $permissiontoadd) {
 				$filetomerge->fk_product = $object->id;
 				$filetomerge->file_name = $filetomerge_file;
 
-				if ($conf->global->MAIN_MULTILANGS) {
+				if (!empty($conf->global->MAIN_MULTILANGS)) {
 					$filetomerge->lang = $lang_id;
 				}
 
@@ -271,7 +271,7 @@ if ($object->id) {
 	if (!empty($conf->global->PRODUIT_PDF_MERGE_PROPAL)) {
 		$filetomerge = new Propalmergepdfproduct($db);
 
-		if ($conf->global->MAIN_MULTILANGS) {
+		if (!empty($conf->global->MAIN_MULTILANGS)) {
 			$lang_id = GETPOST('lang_id', 'aZ09');
 			$result = $filetomerge->fetch_by_product($object->id, $lang_id);
 		} else {
@@ -305,7 +305,7 @@ if ($object->id) {
 			print  '<table class="noborder">';
 
 			// Get language
-			if ($conf->global->MAIN_MULTILANGS) {
+			if (!empty($conf->global->MAIN_MULTILANGS)) {
 				$langs->load("languages");
 
 				print  '<tr class="liste_titre"><td>';
@@ -316,7 +316,7 @@ if ($object->id) {
 
 				print Form::selectarray('lang_id', $langs_available, $default_lang, 0, 0, 0, '', 0, 0, 0, 'ASC');
 
-				if ($conf->global->MAIN_MULTILANGS) {
+				if (!empty($conf->global->MAIN_MULTILANGS)) {
 					print  '<input type="submit" class="button" name="refresh" value="'.$langs->trans('Refresh').'">';
 				}
 
@@ -328,7 +328,7 @@ if ($object->id) {
 					$checked = '';
 					$filename = $filetoadd['name'];
 
-					if ($conf->global->MAIN_MULTILANGS) {
+					if (!empty($conf->global->MAIN_MULTILANGS)) {
 						if (array_key_exists($filetoadd['name'].'_'.$default_lang, $filetomerge->lines)) {
 							$filename = $filetoadd['name'].' - '.$langs->trans('Language_'.$default_lang);
 							$checked = ' checked ';
diff --git a/htdocs/societe/paymentmodes.php b/htdocs/societe/paymentmodes.php
index 20cce294586..e7899db813e 100644
--- a/htdocs/societe/paymentmodes.php
+++ b/htdocs/societe/paymentmodes.php
@@ -1467,7 +1467,7 @@ if ($socid && $action != 'edit' && $action != 'create' && $action != 'editcard'
 				$allowgenifempty = 0;
 
 				// Language code (if multilang)
-				if ($conf->global->MAIN_MULTILANGS) {
+				if (!empty($conf->global->MAIN_MULTILANGS)) {
 					include_once DOL_DOCUMENT_ROOT.'/core/class/html.formadmin.class.php';
 					$formadmin = new FormAdmin($db);
 					$defaultlang = $langs->getDefaultLang();