Questions about Bitcoin Testnet

What version of testnet is included with the Bitcoin Knots executable? I’m not on my node right now, but I recall seeing something like bitcoin-test in the bins folder. Does this run on testnet3 or testnet4 by default?

You can run either one. I think it defaults to testnet3, but you can switch it to testnet4 easily.

Isn't testnet4 just an upgrade to fix some bugs? I found some info saying we should transition to it.

Exactly, testnet4 addresses timewarp attacks, but it also introduced some new issues. Like, mining difficulties jumped unexpectedly because of it.

So, it’s unclear which one I should be using, testnet3 or testnet4? I don’t want to waste time syncing testnet3’s massive size.

Just pick whichever you feel comfortable with. Not like one is clearly better than the other. If you want to avoid syncing, maybe try regtest?

Can we get all this info on the full node console? Like the current block size or logs?

Yeah, there are many options. If you don’t want to download much, go with regtest. It allows for local testing without the heavy load.

That "test_bitcoin" executable in the bin folder... is that for launching a node in testnet? I doubt it.

Nah, that's just for unit testing. You need to run bitcoind or bitcoin-qt with specific flags to launch in testnet.

If I’ve been running with assumevalid=1, does that mean I’ve actually been on a zero state?

You should check the debug log for that info, it should indicate the assumption status there.

So, I won’t see if assumevalid is active in the console, huh? Just in the log?

Yup, it’s a bit hidden. You can usually find your assumption status in your debug logs.

I get that. But it'd be easier if we could check this directly in the GUI, right?

Yeah, ideally, but that’s not how it is now. Keep your configurations organized to avoid mixing things up.

You should definitely go for the latest version of testnet, which is v4. It's improving despite some hiccups.

But there’s no ETA on the next major updates, right? Seems like it’s still in draft.

Right, no ETA yet. Just keep an eye on GitHub for updates.

Thanks for sharing those links! Learning all this is kinda overwhelming.