I just upgraded from v.3.5.5 to Version 4.3.9, all my custom fields no longer show up on page. I still see them in edit mode, but they don’t show up when live. I am a bit lost, could you give me some hint about finding a solution? Thanks.
Sorry about that.
Probably you could be using outdated code to display the fields.
Have a look at this link: http://www.advancedcustomfields.com/resources/displaying-custom-field-values-in-your-theme/