In the new version I do not see the close board button

[Fiore C_ Londino]

I am a member of the board, the only member in this case.  

[Dave Mathijs]

Hi @Fiore C_ Londino welcome to the Atlassian Community Forums!

To close a board:

1. Open the board menu by selecting Menu (...) from the header

2. Select Close board

⚠️ Only board admins and Premium Workspace admins can close a board. Other board members will receive a notification that the board has been closed.

[Fiore C_ Londino]

It does not appear 👇🏽

[Fiore C_ Londino]

It is on my Private Boards and I am the only member.