Reload command?

I have a general question I am not sure if this is the correct forum to post my topic. If anyone can point me in the right direction i would greatly appreciate it. This past week our asterisk box suddenly was not being responsive by not processing calls. Which lately has been a pain, but also a good learning experience. I went ahead and logged into the box and ran asterisk -r to go into the asterisk console and ran a reload command. The system started working within a few minutes. The next work day my co-workers noticed a change in the message being outputted when he ran the extensions reload command after updating the name of one of the extensions a message popped up stating “The extensions reload command is deprecated and will be removed in a future release” and the phone system kept working. All the boxes in my environment run Asterisk 1.4.13 I want to know what exactly does the reload command change as oppose to doing a service restart command and if it can be undone. Thanks in advance!!!