What happens when you try to purchase the app in the App Store on iOS 9? 

You need to put the sublime package folder into the Local Files/#Textastic folder and it should work. So, if you create a folder in #Textastic and then put your .sublime-syntax file in there, it should work. Just make sure that the folder does not end in ".tmbundle" since this is reserved for TextMate bundles.

Sorry, but I cannot seem to reproduce this issue. Can you send me a video of when this happens? Please have a look at this article on how to record the screen on iOS: https://support.apple.com/en-us/HT207935

The current version of Textastic requires iOS 11, but you should be able to purchase Textastic 7 on a device with iOS 11 installed and then attempt to download it from the Purchased tab in the App Store on your iOS 9 device. It should ask you if you want to download the last version that was compatible with your device - Textastic 6.3.2 supported iOS 9. 

It seems like the Select button isn't shown sometimes. In that case tap Cancel and then tap Open... again. Looks like an iOS bug. 

Currently, it's not possible to adjust the light height, sorry.

Please try the following to import an image from the photo library: 

• go to a directory in Local Files or iCloud
• tap on the "+" button in the bottom toolbar
• select "Image"
• pick an image from the photo library
• enter a file name
• tap "Done"

There's a read-only option in Textastic's settings that disables the keyboard so that you cannot modify a file. Please double-check that this setting is disabled.

Please try to select "PHP" as the syntax definition in the File Properties.

Yes, currently this is a two-step process. I'll consider letting you select a target directory when copying a file.