Vaadin 14 question: MPR + Vaadin 7

We are in the very beginning stages of converting our app from Vaadin 7 to Vaadin 13+. At this point, we have a mostly working app that is MPR + Vaadin 7. The only thing that is currently using Flow stuff is the outermost shell, as per the MPR migration guide. I currently use the Navigator route ( https://vaadin.com/docs/v13/mpr/introduction/step-3-navigator.html#no-mixing ). Also, I use a custom Vaadin 7 style via MprTheme, and thus do not use @HtmlImport yet to import any style stuff. I am having some visual problems with IE that I was sort of hoping to fix with App Layout, which of course has API changes between Vaadin 13 and Vaadin 14. Really don’t want to have to change that in a month or so when Vaadin 14 is officially released. According to https://vaadin.com/blog/npm-related-dx-improvements-to-delay-vaadin-14-release-vaadin-15-postponed-to-december, Vaadin 14 is mostly ready, but that we would need to use compatibility mode. Now, for our app, as implied above, we just started it, which means I don’t use any new or advanced features yet. So should I use compatibility mode in my MPR + Vaadin 7 situation, or should I go with the official migration steps https://vaadin.com/docs/v14/flow/v14-migration/v14-migration-guide.html#migration-steps?