I am sorry for all whom expect a migration via magic button or script able in a couple of hours to do the job or solve it with find and replace, it did not work for me at all.
I am working in moving a large invoicing web/app from 0.13 to 0.14 and tasks are really tough, 0.14 is great but it changes a lot of ui behaviours … 
I know a migration guide is coming but distance is much longer that one digit.
There is a lot of work behind and in any point apps has to move forward, updated, bug fixed, etc
A couple of things I found just beginning:
0) You will not have src in node-modules so for every Quasar element you have to declare and import, for instance it is how things should be done. In some points I had used quasar 0.14 src to go further than current documentation.
- Layout has to be adjusted, one should be learn how new layout can be set and make changes. No Drawer. If target app use slots for layouts you have to change some labels and play. 0.14 layout is much easier by far in this release, so one can take this as housekeeping, and simplify code.
- Import Utils does not work, so all elements have to be imported individually, specially dom, format functions, etc.
- Buttons, changing <button to <q-btn, I am afraid it will not be enough, events can work but style has to be checked, and dynamic use of icons has to be moved to q-icon and use “name” prop for the icon.
- Icons and style is another point to consider, it depends on what icon set your app is using (material, fontawesome, etc.)
In target app main.js Icon set should be imported, load style theme mode (css or styl) - Toolbar, another brick in the wall, in 0.13 is a class div and in 0.14 use <q-toolbar, anycase class and style has to be reviewed.
- Some app css styles using classes for toolbar or button will not have effect as html objects classes are renamed with qt, so app stylesheets has to be reviewed. This is a big issue pretty normal by the way with ui updates.
- Autocomplete is an example of changes, in 0.13 my app use input inside autocomplete and in 0.14 this is reversed
Despite I have my own modifications of autocomplete and data-table all elements has to be revised, because usually elements has others elements dependencies, so process will be a long cascade of changes.
So make your space, read carefully current 0.14 doc and then be patient and review 0.13 code, the final results will be worth, but it will take patient and time, I am still in the process.
I have to confess that sometimes I thought if it was not better to start the whole UI of the application again. I think it would be helpful to get familiar with 0.14 in a new application and then later try to migrate others. 
Think that as in life, inevitably to go forward implies to drop some older ways of doing and learn/apply other methods … we are not in a position of judge these changes, only in a point to understand and implemented them for our target application users benefits. 
