A wiki can be made readonly like so:
```
$wgReadOnly = true;
```
If the editor has been opened before read only mode has been invoked, and an edit is completed with the **mobile source editor**, when the save fails, a toast is presented with a generic error message, but the toast is not visible until you scroll down, and the toast appears "underneath" the article content. The error message should probably display the "apierror-readonly" message [EditorOverlay.js#L285](https://github.com/wikimedia/mediawiki-extensions-MobileFrontend/blob/f4c03a10ce202eb70b7b4efd1fe62f58d2c057b0/resources/mobile.editor.overlay/EditorOverlay.js#L285)
{F18725876}
= Acceptance criteria
[] Make sure any error is displayed inside the editor itself, above the preview, using errorbox class (note other box styles may be inside mobile.special.styles.
[] Remove code relating to toast error handling.
[] Include and display the apierror-readonly error message when this error occurs
Mock:
{F22282439}
= Developer/designer notes
Code lives inside MobileFrontend.
= QA steps
== read only mobile
Open the mobile editor.
While open, ask a developer to enable
```
$wgReadOnly = 'This wiki is currently being upgraded to a newer software version.';
```
[] Does the read only message show inside the editor when you try to save your edit?