Does the migration required any user-side action?
I had a seed of ARK wallet written somewhere - should I perform any action, or my funds will be still accessible with this old seed?
Nothing needs to be done from user, user shouldn't experience any difference when interacting with Ark blockchain all of this happened in the "back" with the ones who are running the network (delegates).
Thank you for your answer, I keep my ark rather as longterm investment - it is not worth much but it is one of many "lottery-like" investement - it would be so bad if ARK won but I lost it due to missed action

What's up with the latest
Ark price spike? Am I seeing this correct or is a glitch?

just open bittrex 1D chart you will know the price had touched $ 0.97 a few days ago
you can also see it on upbit exchange or oKex chart,
your price its as seen on binance,
so the price is correct as seen on all major exchanges, its not a glitch
It was near $10USD some day in the past
