Open links to sites outside of SharePoint.com domain in a browser by default. The SharePoint app doesn't handle 3rd party web app authentication well. For example, if you open your SharePoint Online site in the app and then select a link from a page in your SharePoint online site to your on-prem site, it gives a 404 error. The SharePoint app features also differ from what users expect to be able to do in their default browser with web apps other than SharePoint. After you select an external link in the SharePoint app, there is an option to open it in a browser, but users get the error message first. So they may not realize they can open it in a browser and have it work correctly. Another option would be to have a setting for each hyperlink throughout O365 to force opening in a new window or to open in the same window. Even if you left the default behavior as it is currently, it would at least give content editors the option to force one or the other to resolve the issues which result in external links being opened in the SharePoint mobile app. Without this change, we're stuck with promoting the web-only version of our SharePoint Online site to our employees instead of using the SharePoint mobile app.

Thanks for your consideration

The Sharepoint iOS mobile app is showing 2 site icons for each Yammer group that is now integrated with O365 groups. I noticed this because updates I made to the Yammer site home page didn't seem to be reflected but then I realized that they are if you click on the icon that takes you to the Yammer site. However if click on the other icon (same name but unbranded) you get the O365 group site home page for the same site. For example, my SP app shows me 2 icons for the 'Portland' group - 1 takes me to the Yammer site home page, and 1 takes me to the O365 group home page. When I checked the O365 group list from Outlook, I can't actually open it there but I can see the old Outlook interface blurred out in the background and I get a redirect that says 'This is a Yammer group - Go back to Yammer.' So it's just the one group but with 2 different icons and 2 different home page landings which is problematic. It's this way across the board for our Yammer integrated sites.

Although you can view thumbnails within a photo-gallery, tapping on a thumbnail produces no result.

Furthermore, this causes all navigation on the page to freeze (no scrolling); the only option at this point is to use the top level navigation to return to your "frequent sites" or "subscribed sites" page.

Using this method, you are able to return to the homepage (tenant level) of the site that has the photo gallery. Tapping and holding on any link within the homepage prompts the last image you tried to tap to pop up momentarily.

This behavior is observed in both communications and modern sites.

Viewing on an iPad Pro; however, the result is the same on iPhones. (All running iOS 11.)

There is no issue when viewing the gallery from a desktop environment, however, even from a Mac computer.