ELS: 

• All VLAN stuff under "ethernet-switching-options" moved under "vlans" 

• ethernet-switching-options  >>>  switch-options

Enhanced Layer 2 Software (ELS) is a standardized Layer 2 configuration syntax that
addresses customer requests for a common Layer 2 configuration for Junos OS

Enhanced Layer 2 Software (ELS) provides a uniform CLI for configuring and monitoring Layer 2 features on QFX Series switches, EX Series switches,
and other Juniper Networks devices, such as MX Series routers. With ELS, you configure Layer 2 features in the same way on all these Juniper Networks devices.

Getting Started with Enhanced Layer 2 Software

https://www.juniper.net/documentation/en_US/junos12.3/information-products/topic-collections/ex9200/software-all/getting-started-els.pdf

Using the Enhanced Layer 2 Software CLI

https://www.juniper.net/documentation/en_US/junos/topics/task/configuration/getting-started-els.html#jd0e20