diff --git a/system/libs/pot/OTS_Guild.php b/system/libs/pot/OTS_Guild.php
index bab363a8..a7b56728 100644
--- a/system/libs/pot/OTS_Guild.php
+++ b/system/libs/pot/OTS_Guild.php
@@ -97,7 +97,7 @@ class OTS_Guild extends OTS_Row_DAO implements IteratorAggregate, Countable
  *
  * @param IOTS_GuildAction $invites Invites driver (don't pass it to clear driver).
  */
-    public function setInvitesDriver(IOTS_GuildAction $invites = null)
+    public function setInvitesDriver(?IOTS_GuildAction $invites = null)
     {
         $this->invites = $invites;
     }
@@ -107,7 +107,7 @@ class OTS_Guild extends OTS_Row_DAO implements IteratorAggregate, Countable
  *
  * @param IOTS_GuildAction $requests Membership requests driver (don't pass it to clear driver).
  */
-    public function setRequestsDriver(IOTS_GuildAction $requests = null)
+    public function setRequestsDriver(?IOTS_GuildAction $requests = null)
     {
         $this->requests = $requests;
     }
diff --git a/system/libs/pot/OTS_GuildRank.php b/system/libs/pot/OTS_GuildRank.php
index a8832faa..5e8ffb92 100644
--- a/system/libs/pot/OTS_GuildRank.php
+++ b/system/libs/pot/OTS_GuildRank.php
@@ -60,7 +60,7 @@ class OTS_GuildRank extends OTS_Row_DAO implements IteratorAggregate, Countable
  * @throws PDOException On PDO operation error.
  * @throws E_OTS_NotLoaded If given <var>$guild</var> object is not loaded.
  */
-    public function find($name, OTS_Guild $guild = null)
+    public function find($name, ?OTS_Guild $guild = null)
     {
         $where = '';
 
diff --git a/system/libs/pot/OTS_Player.php b/system/libs/pot/OTS_Player.php
index 5c1cbf87..7b688d1c 100644
--- a/system/libs/pot/OTS_Player.php
+++ b/system/libs/pot/OTS_Player.php
@@ -2026,7 +2026,7 @@ class OTS_Player extends OTS_Row_DAO
  * @param OTS_GuildRank|null Guild rank (null to clear assign).
  * @throws E_OTS_NotLoaded If passed <var>$guildRank</var> parameter is not loaded.
  */
-	public function setRank(OTS_GuildRank $guildRank = null)
+	public function setRank(?OTS_GuildRank $guildRank = null)
 	{
 		if(isset($guildRank))
 			$this->setRankId($guildRank->getId(), $guildRank->getGuild()->getId());
@@ -2632,7 +2632,7 @@ class OTS_Player extends OTS_Row_DAO
  * @throws E_OTS_NotLoaded If player is not loaded.
  * @throws PDOException On PDO operation error.
  */
-	public function setSlot($slot, OTS_Item $item = null, $pid = 0)
+	public function setSlot($slot, ?OTS_Item $item = null, $pid = 0)
 	{
 		static $sid;
 
@@ -2776,7 +2776,7 @@ class OTS_Player extends OTS_Row_DAO
  * @throws E_OTS_NotLoaded If player is not loaded.
  * @throws PDOException On PDO operation error.
  */
-	public function setDepot($depot, OTS_Item $item = null, $pid = 0, $depot_id = 0)
+	public function setDepot($depot, ?OTS_Item $item = null, $pid = 0, $depot_id = 0)
 	{
 		static $sid;