Affinity Designer 1.8 is a significant change to the currently shipping 1.7 version. Files edited in this version will not be backwards-compatible with the shipping 1.7 version. As such, we would not recommend using this 1.8 version for critical or production work at this stage. It is inevitable that there were will be a number of issues with 1.8 but we hope these will be minor and aim to resolve any issues very quickly, so please use it and explore the improvements, but also do keep in mind that you may find snags and we would appreciate your help with finding and reporting these to us.