What does "update" mean?

to make something more modern or up to date...

... in what context?

If you see an, 'Update' tag in the gui, it usually means that a card had some flaws or errors in the post production or possibly now has been remastered to a higher resolution, colour balance etc.

So, the card has been, 'updated' to improve the quality in one form or another. It's usually all good 😊

Means, also : beware, for very often I notice you loose some clips doing the update.
Hence I myself NEVER do an update without making a copy of the card directory before, to be able to return to previous version if clips have been dropped in the "update".
(Led me not to update 99% of the cards tagged this way... but I use vghd/istripper ony in 1080p, also.)