Can't send grins

I’m stuck, any advice on what to dig into next would be great (unless I should open an issue in Github):

Command on 0.5.1:

~/.grin$ grin --floonet wallet -p XXXXX send -d "http://XX.XX.XX.XX:13415" 23.00


Wallet command failed: LibWallet Error: Client Callback Error: 
Posting transaction slate (is recipient listening?)

Listening wallet on 0.5.1:

20190112 09:52:03.098 ERROR grin_wallet::controller - Request 
Error: Error { inner:
Generic error: Invalid request body: invalid type: string "Coinbase", expected 
struct OutputFeatures at line 1 column 237 }

Either you or the person you are sending to needs to upgrade to the latest version

Upgrading the listening wallet to 0.5.2 fixed it, thanks!