New and legacy PC and client switching issues and solutions

A.PC end of the new and old version of each other to increase the entrance
B.PC old version increase mask to remind users to use the new website
C. Give old users some time to adapt to the use of new sites, new clients, to the user transition time.
D. The old and new version of the data is out of sync problem: The current is to migrate the basic data and products to a new version of the database, the old database is forbidden to modify the underlying data, the deadline to migrate the old business data to the new version of the database.
E. When forcing users to use the new website or the new version of the app, consider whether or not the loyal customer will lose the problem and minimize the problem.
F. The old version does not provide registration function, or register directly to the new version of the registered address registration, the new version provides the registration function.
G. With data migration in mind, the underlying data is easily modifiable and involves the updating of business data that relies on underlying data.
Numbers can be used when numbering is used. Because numbers are best adapted for data migration, the ID is the worst.