nvm: "Aliases in subdirectories are not supported" when removing or updating lts/* alias

Hi there, my issue is that existing alias lts/* cannot be changed.

System: macOS 10.12.1 nvm version: 0.32.0

nvm ls return follow list of aliases:

         v4.7.0
->       v6.9.2
default -> stable (-> v6.9.2)
node -> stable (-> v6.9.2) (default)
stable -> 6.9 (-> v6.9.2) (default)
iojs -> N/A (default)
lts/* -> lts/argon (-> v4.7.0)
lts/argon -> v4.7.0
lts/boron -> v6.9.2

lts/* points to uninstalled version lts/argon (v4.7.0).

I would like to change lts/* alias to lts/boron.

Have tried command:

nvm alias lts/* lts/boron

but it returned error:

Aliases in subdirectories are not supported.

PS: Alias lts/* was created by nvm itself (not by me), I just want to update it.