Denver Comic Con announced changes Thursday for its 2017 event in an effort to keep the event safe and family friendly.

Attendees are encouraged to dress for the occasion but will have to adhere to the new dress codes. They include no bare chests and no thongs or "plumbers' butts." Some type of shoe must also be worn at all times.

In addition to attire, Comic Con is making changes to its policy regarding props. All firearms and replica firearms will be banned regardless of their material. Bladed metal or wooden weapons such as axes, daggers, hatchets, knives and swords, pocket blades, ninja stars won't be allowed either according to the groups web site.

Other props, such as bats, swords, hammers and shields made from foam or plastic are still encouraged provided they fall within the existing polices.

Comic Con says it understands the changes will impact popular costume choices, but says the changes are necessary to make sure the event is safe and fun for everyone.

You can read the full Cosplay rules for Denver Comic Con here.