Package hyperref Warning: Option `pdfpagelabels' is turned off
(hyperref) because \thepage is undefined.
Hyperref stopped early
Google was my friensd this day since the first search result provided the appropriate workaround:
Cheers to localghost, whose answer allowed me to skip reading the change logs of the hyperref package at such a stressful time.
In fact, all the new warnings I got were related to the update of beamer and hyperref.
This blog entry : http://texblog.net/latex-archive/presentations/beamer-warnings/ presents a step by step workaround. Thanks Stefan.