Sorry it took so long to answer here, but at the moment we are working on the upgrading guide. Here are the Team notes about the process: https://gist.github.com/hawkeye64/da4b4d662ab1484bd0b532ffd871679e
and Matyas from the staff generated a comparison between 0.17 and 1.0:
We plan to maintain 0.17 for at least a year, but we won’t be adding new features. There will be backported security fixes and we will try to keep packages modern.