I own a business which is selling enough to pay 3 people, running 1.3 in a template which does not work immediately in 1.4 or 1.5.
Our store has been customized in many places, including modules and some core files, althought it is properly tracked with a code repository.
Our goal is to sell more, and for that it could be useful to have the features that 1.4 or 1.5 have... so my question is: Should we upgrade? If we should, what version is it worth to upgrade? Of course 1.5 has more features, but 1.4 might be more similar so the change might be less traumatic.
Of course, we do not want to lose any ranking in Google, we do not want to have any new 404 error page, etc....
What is your expectation in terms of time for a migration like this?
Please consider this is a running business, and our salary depends on the fact that the store keeps running. Also consider that we want to use the same template, as we do not want customers to feel both changes at the same time...
Any comment will be appreciated.
Thanks