Slow log content changed with ES 2.0

Does anybody know why information written into slowlogs changed in ES 2.0?

In ES 1.* versions it looked like
[datetime][TRACE][] [NODE] [index][0] took[1.6s] ...

But in ES 2. info about NODE and INDEX is missing*
[datetime][TRACE][] took[1.3s] ...

Is there any way how to change structure back?
I compared logging.yml from ES 1.* and ES 2.* but it didn't seem to be the cause.