Do I have to have the same OFP version level as the host in order to connect?

OFP gives you a minimum amount of leeway in allowing clients and servers of different OFP versions to connect with each other. Here's a chart:

Dedicated server version Supported client versions
1.30 1.30
1.40 or 1.42 1.40 or 1.42
1.45 or 1.46 1.45 or 1.46
1.47 beta or 1.48 beta 1.46

(Source: Ondrej Spanel, BIS' Lead Programmer)