Trading Procedures:
- The exchange must state what security measures are in place should it operate 24/7 or at certain hours and when security updates would be rolled out.
I would leave that at the discretion of exchange operators. I'm sure they wouldn't want to disclose all types of security and their rollout times.
I think the intent here is that an exchange has two ways to operate and should disclose their intent either way:
1) They are periodically closed (and state exactly when they are closed), to allow for maintenance and security updates.
2) They are open 24/7, and thus, owe the community an explanation as to their ability to provide security updates if they do operate 24/7.