Tier 2 Sub Category Clarification

[RCole]

Hi

I'm struggling to find any guidance on what these cover, can any one point me in the direction of any resources? We've previously sponsored someone successfully about a year ago but I can't remember which one we selected, or even if they are the same.

Tier 2 (General - switching immigration category)
Tier 2 (General - Tier 4 graduate switching to Tier 2)
Tier 2 (General - changes of employment - ISC liable)
Tier 2 (General - changes of employment - ISC exempt)
Tier 2 (General - extensions - ISC liable)
Tier 2 (General - extensions - ISC exempt)
Tier 2 (General - new hires - high earners - ISC liable)
Tier 2 (General - new hires - high earners - ISC exempt)
Tier 2 (General - high value inward investment - ISC liable)
Tier 2 (General - high value inward investment - ISC exempt)