Today (or in the coming days) there will be an update to the visibility of fleets in high orbit.

Baseline visibility will be increased from 25,000 to 30,000 km.


The updated visibility will work under the satellite visibility rules
This means that all fleets that are outside the local coordinates of 30k will not be visible in the galaxy, but will become visible according to these rules.

When flying into high orbit the visibility of all fleets will be revealed.
In other words, if you see a hidden fleet in the fleet panel, you and your allies will see it in the galaxy.
The Phalanx will also allow you to see the hidden fleet.

In the current version free-flying fleets are not adapted to work with object detection, but the new update will fix this.
It will therefore become possible to search for comets using fleets.

Answers to basic questions:
> How do I know if there's an enemy fleet hiding in local coordinates?
Just send any fleet to the coordinates, and check if there is an enemy fleet in the galaxy.
And if you have a Telepathist, all fleets will immediately show up in the Fleets panel or spaceport.

> How do I hide a fleet at local coordinates?
Send a fleet with 1 unit to high orbit defense and use free flight to send the unit out of range.
If necessary, send the remaining fleet to defend that unit. After reaching the target it will stand next to it or merge.
Your ally can also stand beside you if it chooses to target your fleet.

The update is installed.

How does this affect Scrouge who are not visible in the first place unless you end up in orbit with them.

also will we now be alowed to send SPY units to high orbit to look for fleets? currently it seems that I can only spy a planet or moon like object/ope/astirode
.

Once again, poor implementation of a change by developers.
Now all our fleets are invisible, not returning, or not engaging targets.
If Developers want to make changes, more testing is required in order to ensure that any changes are free of issues.

That wasn't the issue with recent changes. It was sort of Y2K, a problem that was present all along but only triggered at a certain point.