In preparation for the adoption of SeisComP for routine use in Western Canada, a validation exercise was undertaken. Location accuracy was evaluated based on two catalogues, generated using SeisComP and the legacy seismic analysis tool, Antelope. Magnitude validation additionally used the ComCat catalogue located by the USGS and affiliated agencies. In all approximately 400 matched seismic events were compared. The 95th percentile epicentral difference between the two systems was 15 km. When the epicentral difference was computed as the distance between the respective epicentral error ellipses, the 95th percentile dropped to 8 km. All events with epicentral differences greater than 20 km were in regions of poor network coverage and featuring a low number of arrivals, large primary azimuthal gaps, or a combination of the two. The median magnitude difference between SeisComP and ComCat was found to be negligible, when SeisComP was configured according to the IASPEI recommended procedure. Antelope was found to use a different method of amplitude estimation, which resulted in amplitudes 0.06 magnitude units larger, and took an additional step of subtracting the noise RMS from the peak amplitude, resulting in amplitudes 0.04 magnitude units smaller. Significantly, it was observed that Antelope switched from vertical to horizontal amplitudes in July 2021, resulting in median magnitude differences approximately 0.2 magnitude units larger. By demonstrating under what conditions earthquake monitoring systems may give different epicentral and magnitude estimates, and quantifying those differences, we ensure continuity of the earthquake catalogue over time, and commensurability between different regions and agencies.