解决因升级造成的兼容性问题

[yyc-git]

refer to:
说透低代码-17｜兼容性问题：如何有效发现兼容性问题？
说透低代码-18｜兼容性问题：如何有效解决兼容性问题？
https://time.geekbang.org/column/article/564236 -> 评论

• TODO 处理后端数据兼容性

TODO 加入数据adapter层？

疑问

• if app or package binary change, then only can use if else in default/meta/ code instead of update them in database!?

answer: no, can still update in database by:
1.use old default/meta/ code to get their data(all extensions,contributes,packages,... data)
2.use new default/meta/ code to write them to a new binary!