Just like with if..endif, the syntax of while..endwhile has changed as well:
Example#1 Migration: old while..endwhile syntax
while ($more_to_come);
...
endwhile;
Example#2 Migration: new while..endwhile syntax
while ($more_to_come):
...
endwhile;
If you use the old while..endwhile syntax in PHP 3.0, you will get a never-ending loop.