However, registration *is* required before filing a lawsuit.

I thought it was only required in order to have a certain type of damages awarded (which may make it economically infeasible to sue without have filed, but strictly speaking not necessary).

The article linked in the text Microsoft has begun flooding media outlets with information advising users to switch to an alternate browser while quotes a Trend Micro spokesman advising users to switch and a Microsoft spokesman explicitly saying he can't advise users to switch over one flaw. This contradicts the summary text.