Using the "Share" command method I mentioned, you can select a specific app for different file extensions. So if you use share to open Textastic for .txt, and another app for .md for example, the system will remember this selection.

I also wish this would have a better UI - similar to the Mac, but that would be something Apple has to change.

In the Files app, open the context menu of the file and select "Share". Then select Textastic. From now on it should open files with the same file extension in Textastic.

Alternatively, you can use the "Open…" command in Textastic to pick a file using the Files user interface.

This is fixed in Textastic 10.5.2.

This is changed in Textastic 10.5.2:

The app no longer prompts users to connect to a Wi-Fi network when starting while Airplane mode is enabled. This behavior was removed by deleting UIRequiresPersistentWiFi from the app’s Info.plist.

This is fixed in Textastic 10.5.2. 

Thanks again for letting me know about this - I'm honestly not sure how I missed this - looks like it was like that for years 😬

Do you want to have the option to order the results when doing a filename search or when doing a file content search?

When doing a filename search, Textastic performs a fuzzy search and displays the files with the best matching name first, so a sort order doesn't make a lot of sense.

So I assume you are asking for sorting the results of a file content search?

No, the WebDAV server is only started manually. See Settings -> WebDAV server.

This was required in earlier versions of iOS to be able to start the WebDAV server and bind it to the local Wifi ip address. 

I need to check if setting UIRequiresPersistentWiFi is still required in the latest version of iOS.

I can see how the system prompt that is shown in Airplane mode might be misleading.

In order for the WebDAV server to work, Textastic sets "UIRequiresPersistentWiFi" to YES in its Info.plist file.

This makes sure that a Wifi connection is enabled if possible. If you are in Airplane mode, this results in a system popup that asks you to connect to a Wifi network. You can just close that.

Textastic doesn't actually connect to the internet when you start it. Connections are only started when you connect to a remote server.

You can read more about UIRequiresPersistentWiFi in Apple's developer documenation at: https://developer.apple.com/documentation/bundleresources/information-property-list/uirequirespersistentwif