OxyExtenden Plugin comes with a Maintenance Mode/Coming Soon Mode that you can use on specific pages or all over the site.
In order to use Maintenance Mode/Coming Soon Mode, head over to Oxygen > OxyExtended > Maintenance Mode.
Here, you'll get an option to Enable Maintenance Mode/Coming Soon Mode.
Once you enable the Maintenance Mode/Coming Soon Mode, you will get an option to choose the type. You can either opt to display Coming Soon Mode or Maintenance Mode.
The next option in this section is to choose the Coming Soon or Maintenance Page. You can further decide who can access the site even when the Coming Soon Mode or Maintenance Mode is enabled from Logged In Users, Administrator, Author, Editor, Contributor, and Subscriber.
The next option here is to include/exclude the URLs on which the Coming Soon/Maintenance Mode page is being displayed. Finally, you can also whitelist the IPs so that Coming Soon/Maintenance Mode work on these IPs.
This was all about using the Maintenance Mode/Coming Soon Mode in OxyExtended Plugin. Feel free to get in touch with us in case of any questions.