We are in the process of upgrading from Magento 1.7 to 1.9 and am writing to ask if anybody has experience with what to do and not to do in order to "preserve" rank in Google search. Perhaps I am off track here, but I remember hearing from an SEO expert a while back that it's important not to mess up when launching a new site. I am grateful for all tips!
My experience says that upgrading from 1.7 -> 1.9 is relatively smooth sailing. Only thing you have to pay attention is that some additional forms have new formkey anti-bot measure and thus they do not work unless you add to those forms:
<?php echo $this->getBlockHtml('formkey')?>
None of it has anything to do with SEO however.