Test on both Android and iOS devices: Enter a site and enter a PAGE activity. Check you can see the reading mode button on the top toolbar. Click it and check something has changed on the page: Images and media has dissapeared. Collapsible header is collapsed (if any). Activity information (description and completion info is hidden). Background color changes to black. Check the button has now gray background to indicate reading mode is enabled. Click it again and check it opens a settings modal. You can play and check all the settings: Text size allows to resize text (only content) from 75% to 200% on 25% steps. Theme will change background and text color to match the selected settings. (Match app matches light or dark depending on app settings) Show images and media will show/hide videos and images from the content. Exit reading mode will disable the reading mode returning to the original state. If you navigate to Next/previous activity with reading mode enable it will be disabled if the destination page has no reading mode. (Book index and glossary list have no reading mode). Otherwise it will be kept enabled. This also happens whe navigating through book pages or glossary entries. Repeat the test with glossary (single entry view) and book (page view). Check you can navigate pages of book with the reading mode enabled (which is maintained enabled). In glossary the swipe navigation maintain the reading mode enabled. Note: navigation from one page with reading mode to another will also maintain the reading mode enabled (ie, from page activity to another page activity but also when following links to other activitites). In any cas a flick (flash disable and enable again may occur).