I use WinSCP Portable which means to update I download the new version and then replace the 'data' folder with that of my old version so that all my site definitions are imported. This process of using the portable version and updating in this way has worked well without issue for a long time now. However, updating from 5.5.3 to 5.5.4 I noticed that for sites where I am using a private key, even though my passphrase is saved with the site definition, 5.5.4 keeps asking for my passphrase every time I open a new connection.
See demo - https://i.imgur.com/vgPPOgE.gif
Here my connection has the correct passphrase saved already. I double-click to open the connection and WinSCP 5.5.4 prompts me to re-enter the same passphrase already saved against the site definition. I then paste in the same passphrase in the prompt and my connection is opened successfully. Not sure why it's prompting as falling back to v5.5.3 everything works as it should.