Upgrade YaBB forum from version 2.1 to version 2.4

We have a website that is using YaBB forum software version 2.1. Our users have made 776 Posts within 510 Topics. There are 128 members. We want to upgrade to version 2.4, because recently the forum has been getting too much spam. We have are some important requests: 1. You should first do a complete backup of the existing forum software, templates and database, in case there is any problem 2. It will be a good idea to install 2.4 into a separate directory and then move to this version, rather than simply overwriting, in case there is any problem 3. Please be sure to preserve the custom templates, messages, etc. that we have created