Briefly, what issues can we expect to have upgrading from this ancient version to current? Our current Jenkins VM, is running on a hypervisor that is dying so we need to migrate to a new version of Jenkins and to another hypervisor/VM.
Thanks.
That release is almost a decade old. Be sure to upgrade all plugins to the latest versions after upgrading Jenkins core. You will likely end up with some outdated/deprecated plugins at the end, so after upgrading everything be sure to remove any deprecated plugins or plugins with known security vulnerabilities. And you will also have to deal with a decade worth of breaking changes. Be sure to back up your Jenkins home directory and do plenty of testing, as it will likely take some time and effort to successfully complete an upgrade of this magnitude.
Hi @dpearceFL and welcome to the community! 
You may encounter a mix of surprises, both positive and negative, during your journey here. While that might sound daunting, rest assured that many of us have navigated similar challenges before.
When migrating from such an old version of Jenkins, it can feel like transitioning to an entirely new software platform. You might encounter deprecated plugins, configuration changes leading to job failures, connectivity issues with agents, and more.
If you’re facing urgency due to server issues, I recommend starting by backing up your jobs directory and documenting the list of currently installed plugins. From there, take incremental steps towards setting up the new server.
Here’s a helpful guide to assist you through the upgrade process: Marc’s Napkin Upgrade Guide.