All of our Visualforce pages suddenly stopped displaying all fields and values. I see no changes made to the pages, the underlying classes, the objects and fields referenced, nor to guest profile permissions.
On the Salesforce side, the only message I see is that legacy SOAP API versions were retired today, but I don't see how that comes into play here. Furthermore, they say those versions are usable until the Winter '19 release (we are on Summer '18).

Has anyone seen this before?

i have some requirement where i need a pick list on my VF page , pick  
   list contains all  objects.   based on this pick list value i want to  
   display all fields of appropriate object. for example if i select  
   Account from  pick list then it should show all its fields in the  
   page. please tell me how to do this & send some sample code