Change of Employer - Blue Card

Can someone please confirm if we need to get an approval from Immigration authorities to change employer(Job), i have completed around 19 months with my employer and on my blue Card ?

I checked on https://stadt.muenchen.de/service/info/hauptabteilung-ii-buergerangelegenheiten/1080627/ and here it says that only within first 12 months approval and notification is needed but on some other pages in website still information is contradicting.

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Anyone who had undergone this recently please help!!

Thanks