[Solved] When upgrading to support iPhone X, font display smaller on older devices

Question

That’s neither bad nor unexpected. Without any launch image, the app runs as if this were a much smaller device, e.g. with a screen size of 320 x 480. That is narrower than the iPhone X so it is enlarged (zoomed) to the width of the device screen (so that we letterbox from the top and bottom, but not from the sides, as your first screenshot shows).

With the launch image, that letterboxing and enlargement goes away and you run natively with a screen size of 375 x 812. Now we are seeing more points of width on the same size screen, so the same point size font appears smaller, like a house seen from further away in a wider field of view.

You can easily confirm this by logging UIScreen.main.bounds with and without the launch image.

Accepted Answer

That’s neither bad nor unexpected. Without any launch image, the app runs as if this were a much smaller device, e.g. with a screen size of 320 x 480. That is narrower than the iPhone X so it is enlarged (zoomed) to the width of the device screen (so that we letterbox from the top and bottom, but not from the sides, as your first screenshot shows).

With the launch image, that letterboxing and enlargement goes away and you run natively with a screen size of 375 x 812. Now we are seeing more points of width on the same size screen, so the same point size font appears smaller, like a house seen from further away in a wider field of view.

You can easily confirm this by logging UIScreen.main.bounds with and without the launch image.