transmit old positions

Hi

Some months ago, I started a topic : https://www.traccar.org/forums/topic/past-positions-buffer/

In fact It now works fine, the android traccar client sends old positions to the server.
Are there some kind of limitations to this transmission ?
Is it the same on the android and the iOs versions ?
How many positions are saved in the memory of the traccar client ?
Is this configurable ?
Is there any doc about this feature ?

I ask all these questions because I sometimes use Traccar to log the positions of light sports aircrafts, and the GSM signal is sometimes too weak to enable the transmission of the logged data.
I was considering about building my own tracker and datalogger absed on arduino, but as this feature is implemented, a 50$ smartphone like the UMI ROME X will be sufficient.

Thanks.
Michel

Is it the same on the android and the iOs versions ?

Yes, both iOS and Android versions buffer unsent data.

How many positions are saved in the memory of the traccar client ?

There is no limit. Data is saved in the local device database, so it can handle very big number or positions.

Is this configurable ?

No, but you can clear app data if you want to get rid of old data in the database.

Is there any doc about this feature ?

No. Basically app just saves unsent data and uploads it as soon as internet connection is available. What kind of documentation are you interested in?

So I was wondering at what rate the data is sent, it seems that it is one data per second, but maybe more.
Because if a device holds 2 weeks of data, how long will it take until the real actual position is sent ? I suppose the old data is sent until the buffer is empty and the present position is sent no ? This seems to be like that to my first tests.

Correct, it sends old data first. Rate depends on your internet connection speed.

Thank you!