The rules say that "Small colonies suffer instability every time an immigration event occurs."

I've been wondering about that for a long time, but what exactly counts as an "immigration event?" Is it:

a) Small colonies roll for regime change, unrest and economy change each year (because their population increases automatically each year)

or

b) Small colonies suffer instability only specifically from immigration events from the "A-Base D-Landing" supplement, but the automatic year-by-year immigration does not cause any regime change/unrest/economy change rolls because it's not an event

Which one is correct?

This rule is a victim of me removing the immigration rules from This Space Intentionally when I initially intended to use them in  (A)-Base (D)-Landing (I ended up adopting a different system entirely). I will rectify this for the next update. Please use the rule from the previous update, if you have a copy of those rules and I’ll endeavour to dig up the relevant section from a backup and reply here with the text.

The unrest and crowd dice placed in  (A)-Base (D)-Landing and A Facility with Words can be used to look up an event on the unrest table in the meantime.

My apologies for the oversight.

The original text was:

"If you want to track the exact number of immigrants year to year, roll 2D6 for each colony each year, +1 if Upported, +2 if Colonization, +3 if Exoglobalization, +4 if Futures, +5 if Endgame. If you roll 7 + the heliocentric distance or higher add 1D6 to the population scale due to immigration that year (slightly more than doubling the population). Small colonies suffer instability every time an immigration event occurs."

Please use a rule similar to: "Roll 2D6 for each colony each year, +1 if Upported, +2 if Colonization, +3 if Exoglobalization, +4 if Futures, +5 if Endgame. If you roll 7 + the heliocentric distance, the colony suffers instability".

However I'm working quite a lot in this area of the rules for the next update, so may end up with a different rule entirely.