there is an off-by-one that prevents the dht from working properly, it actively poisons the network. i fixed this in i2pd last year, the code changed so much I think that's where it is located now. there are a few more bugs like that i know of off the top of my head but i'd need more coffee. i got kicked off kovri for trying to fix bugs, good luck to them in the future. they're going to need a major management additude readjustment if they want to provide a proper functioning i2p router, so far all they have done is shoo away competent developers with the way they treat PR.

further updates:

kovri does not provide extra "security" or "quality" as seemingly none of the bugs I and many others fixed in i2pd have been fixed in kovri. that document is a huge load.

if anyone wants to contribute to i2pd see: https://github.com/purplei2p/i2pd/