ATTiny841 not found in avrdude, up to date IDE etc

I'm trying to upload to an ATTiny841. I have lots of experience with the ATTiny84 and have no problems there, but the 841 gives me:

avrdude: AVR Part "attiny841" not found.

I'm running Arduino 1.8.4, avrdude 6.3, and ATTinyCore 1.1.5 (Konde).

I see some discussion of this online, but it all seems old and seems to suggest that up-to-date avrdude should support ATTiny841.

Any thoughts?

If you are doing Upload Using Programmer then you need to make sure you have one of the programmers with “(ATTinyCore)” appended to their names selected from the Tools > Programmer menu.

When doing Burn Bootloader or Upload Using Programmer, or whenever using the Tiny841 without bootloader, you need to select one of the programmers with (ATTinyCore) after it.

They are exact copies of the programmers of the same name defined by official avr board package; it's a workaround for a bug/feature with the IDE that causes it to use the upload recipes defined in the official avr board package, instead of the ones from the board package that goes with the board. These recipes point avrdude to an avrdude.conf that comes with the IDE. Unfortunately that version of the file doesn't support most ATTinys.