the core of the website, needs to be rethinked and improved

Hi, just came across the following phrase: the

core of the website, needs to be rethinked and improved,

Is ‘rethinked’ really an acceptable version of the past participle or is ‘rethought’ still the only choice?

Many thanks,
Torsten[YSaerTTEW443543]

TOEFL listening discussions: A conversation between a student and a campus patrolman[YSaerTTEW443543]

The interesting thing is that the phrase occurred in an offer created by a Canadian company written by Canadians. Maybe because they are from Montreal and English is not their first language they made this mistake?[YSaerTTEW443543]

TOEFL listening discussions: What did the young man do during his last holiday?[YSaerTTEW443543]