Yes. The existing RPIWS281X Channel Output that drives 2 strings of 1600 pixels on a Raspberry Pi will continue to function as long as the rpi_ws281x library maintainer supports the library. DPIPixels is not required for using 2 strings of pixels on a Pi. The advantage of switching to DPIPixels is more outputs (up to 24), and the onboard audio on the Pi does not have to be disabled. If you want Pi pixels and audio without having to use a USB dongle, you can use the 2-output license key and switch to DPIPixels and get your onboard audio back, but you do not have to switch to DPIPixels if you don’t want to.