In the background, Dédale is checking for compatibility issue by analysing your template code and querying Can I email? database.
You can figure out every poorly compatible properties by opening the “Can I email?” panel.A: Name of the property B: Link to open the related property on Can I email? website to have more informations C: Percentage of compatibility
Percentage is calculated by aggregation of the Can I email? supported plus partially supported
Below 20%: we consider the property to be really poorly compatible with email clients, you should avoid using it to ensure your template will work for all your contacts.
Between 20% and 80%: property is considered as partially supported and you may have some issues on some email clients. You should look for a fallback.