In reply to TheDrunkenBakers:
The 45 series, ie 45, 245, 645, 745 and 945 will all be refreshed at different times.
The first of the 55 series came out in June with the 55. I don't think the 645 will be replaced as it was already not being listed as a current model. So you'd need to check whether a likely 255 or 755 would best meet your requirements.
The 245 came out April 2019, and the 745 came out September 2020, which would imply that the 255 will appear first, but who knows when !!