I revoke my complaints
a lot have changed within last 10 game years
Invaders are like cockroachers
200-300 kt groups arriving on regular basis from every place and now I face over 1 mil military group so the fun is officially back

my game was started under 2.11 so it should not be any issue

For some reason, Swarms are extremely hard to find.  Steve said he finds them well enough, however, believe me, or not, I NEVER EVER met a swarm in Aurora C#, and I know a couple of regular players in this forum can say the same.  Regarding NPR you can increase their chances if you want more and there is also another "hack" which is to reduce the chances of ruins (if there are ruins NPR cannot be generated).

I had that issue from around 1. 11 - 1. 12 to even at the beggining of 2. 1 (don't remember exactly which update).  Even adding them in via SM mode didn't work.  I think I saw them once pretty long ago.  A completely fresh install fixed it.  I took the base download and updated it to every subsequent release and now I can get star swarms.

so I am unlucky with Swarm
how about Invaders ?
why so little action here ?

I would say you got lucky.

I have had more than one game end early courtesy of finding the Swarm early in the game, they are brutal to fight early on.

so I am unlucky with Swarm
how about Invaders ?
why so little action here ?

Do you have any Aether Rifts?

Once invaders are active, the chance of any new system containing a rift is 1%. The chance of a rift forming in one of the existing systems is about 1% per year (for all systems, not each).

Once rifts are open, the chance of attack in any given year is about 0.25% * Years Since Invader Activation. So after 20 years, it is 5% per year. After 40 years, it is 10% per year. The size of the invasion force is based on the size of the rifts.

Last game I had 4 separate swarms and only around 60 systems explored by me.  (Mind you I did have three initial NPRs which activated at least one, possibly two swarms) - this after about 10-15 years game time.

For some reason, Swarms are extremely hard to find. Steve said he finds them well enough, however, believe me, or not, I NEVER EVER met a swarm in Aurora C#, and I know a couple of regular players in this forum can say the same.

This was true for me until 2.1.1 - there was a bug that was fixed them that prevented Swarms being generated later in the game, so for us slow-tech conventional start players, we just didn't see them.

Fixed in 2.1.1 and since then I've had a seriously rude awakening... Damn things are murder on a beam-only fleet that can't match their speed   Definitely seem to be generating in decent numbers in my games - I think I've found at least 3 separate Swarms by the time I've hit 150 systems in both my 2.1.1 games, and have been holding border JPs against them and struggling to push them back.

2025 start with increased population
all spoilers on except invaders which were turn on around 2060
year 2100
160 star systems surveyed
2 nprs , 1 rakha world
raiders often , 5-6 precursors worlds
few fast unarmed scouts looking like invaders which were destroyed fast on the border ( combination of dst chain and minefields on empire boundaries )
no combat Invaders so far
either I missed message  no rift was found
no star swarm either
I feel like intensity in my space is a bit too low ( basicly only raiders from time to time)
I remember raiders from VB6 times and know they can hit very hard 

if not aggressive npr with 1mil+ tonnage guarding his gate and waiting for assault there would be little to do

For some reason, Swarms are extremely hard to find. Steve said he finds them well enough, however, believe me, or not, I NEVER EVER met a swarm in Aurora C#, and I know a couple of regular players in this forum can say the same. Regarding NPR you can increase their chances if you want more and there is also another "hack" which is to reduce the chances of ruins (if there are ruins NPR cannot be generated).