Are special characters allowed for an iPhone’s name?

I know how to rename my iPhone.

I'm curious if there is any problem with adding a character to the iPhone's name.

Specifically, can I rename it to "TMH's iP7+" with the plus sign at the end?

I have looked online and cannot find any mention if this is an issue.

Symbols are fine, including a plus sign or even emoji.

You may notice oddness when sharing your Internet connection through Personal Hotspot. Some devices don’t play nice with non-Latin alpha characters, and may display funky characters in the list of Wi-Fi networks (though the connection should work fine).

I suppose your mileage may vary here, but other than that, what @grgarside said.