Strict Standards Error

[Raw Sugar]

This is on vB 3.8.7, running PHP 5.6.31.

This error is showing up most recently on the memberinfo page, but has also shown up in the UserCP. I've looked at the files referenced and can't figure out what it means. I looked up the Strict Standards error in general, but I'm confused about how to fix it for vB files.

A few of the errors I've gotten:

Strict Standards: Declaration of vB_Group_Collection_Discussion::collection_sql() should be compatible with vB_Group_Collection_Message::collection_sql($force_refresh = false) in /home/.../includes/class_groupmessage.php on line 1899

Strict Standards: Declaration of vB_Group_Bit_Factory::create() should be compatible with & vB_Bit_Factory::create($item) in /home/.../includes/class_groupmessage.php on line 2918

Strict Standards: Declaration of vB_ProfileBlock_Infractions::block_is_enabled() should be compatible with vB_ProfileBlock::block_is_enabled($id) in /home/.../includes/class_profileblock.php on line 1942

Thank you in advance for your help!!