Converting from existing Brinks system to Surety. Can I use existing hardware?

I just purchased a condo that has a pre-existing Brinks Security System. The current Brinks contract expires this week.
The existing Brinks system uses the Interlogix Simon XTi-5 panel. All sensors are wireless. I would like to replace the panel with the Qolsys IQ Panel 4 (319.5 MHz radio) but use the existing sensors. Would I need any additional hardware other than the Qolsys panel? I am going to add a few sensors but want to get the current system working with Surety first.

The Simon XTi-5 uses 319.5Mhz sensors compatible with the Qolsys panel 319.5Mhz version. You could reuse the existing sensors with a Qolsys panel without any additional hardware.

One caveat would be if you have any smoke detectors or CO detectors connected to the system, double check their replace by dates. Those have hard expiration dates and need to be replaced when they expire.

I understand that the existing control panel may have a programming password or code held by Brinks. I am replacing that panel in any case. Would any of the sensors have any sort of passcode that I need access to or can I just connect them to the new IQ Panel 4?

The sensors themselves, no. They just broadcast a signal and the panel needs to be programmed to listen to it. Steps to program 319.5Mhz sensors into an IQ Panel 4 are in the link below:

If you have any Z-wave automation devices, many lock models have a local programming code. You may need to factory reset the lock to gain access to its code if you have one.