How to upgrade

Kylin 4.0.0 is the first GA version of Kylin 4, it provided new implementation of its storage engine and query engine. By using Parquet storage to replace HBase storage, Kylin will separate computation and storage , will conform to Cloud-Native trend .

Suggestion

Please check FAQ of Kylin 4.0.0 (FAQ Kylin 4.X) and you can find some tips.

1. Is Kylin 3.x and Kylin 4.x metadata compatible?
2. Is Kylin 3.x and Kylin 4.x pre-calculated cuboid data compatible? If not, will there be a migration plan? 
3. What features will no longer be supported in Kylin 4? And what do Kylin 4 provided ?

In general, please :

1. Purge all cube before your migration.
2. Refine your kylin.properties, make sure you have fully understanding how to configure new query engine and build engine (please check Kylin 4.X Configuration). 

Besides, you can choose to use Tools to migrate metadata from Kylin 2/3 to Kylin 4.0, here is the link: How to migrate metadata to Kylin 4 .