user5152: I've been running bitcoin core 0.15 as regtest, and had X bitcoin in my balance all are from legacy output addresses, As I upgraded to 0.16 core version check in debug the legacy addresses are still validated as mine. but no balance. I wonder will this happen as I will upgrade my wallet at the mainnet as well ?
I wish to be able and support creation of legacy address and SegWit on the same wallet and as of comments on How to generate SegWit address I see I will need to run bitcoin core each time with a new param "-addresstype=legacy" to enable it, so is there a better way ? 
[edit 1] - I should/need to run with same "-datadir" arg ?
[edit 2] - I run it under same -datadir.
[edit 3] - I’ve opened issue 
https://github.com/bitcoin/bitcoin/issues/12872

user208: Quoting Suhas Daftuar's response to the issue you opened:

In 0.16, we changed the consensus parameters for regtest so that segwit was always active. This was mentioned briefly in the release notes https://github.com/bitcoin/bitcoin/blob/v0.16.0/doc/release-notes.md#testing-changes, along with a workaround to replicate the old behavior.
I am surprised that you're not seeing the assertion failure mentioned in the release notes, but I suspect this is the cause of what you're seeing.

So this is expected, but only affects regtest.

5152: <p>I've been running bitcoin core 0.15 as regtest, and had X bitcoin in my balance all are from legacy output addresses, As I upgraded to 0.16 core version check in debug the legacy addresses are still validated as mine. but no balance. I wonder will this happen as I will upgrade my wallet at the mainnet as well ?<br>
I wish to be able and support creation of legacy address and SegWit on the same wallet and as of comments on <a href="https://bitcoin.stackexchange.com/questions/57832/how-to-generate-segwit-address/57836?noredirect=1#comment84934_57836">How to generate SegWit address</a> I see I will need to run bitcoin core each time with a new param "-addresstype=legacy" to enable it, so is there a better way ? </p>

<p>[edit 1] - I should/need to run with same "-datadir" arg ?<br>
[edit 2] - I run it under same -datadir.<br>
[edit 3] - I’ve opened issue 
<a href="https://github.com/bitcoin/bitcoin/issues/12872" rel="nofollow noreferrer">https://github.com/bitcoin/bitcoin/issues/12872</a></p>
 208: <p>Quoting Suhas Daftuar's response to the issue you opened:</p>

<blockquote>
  <p>In 0.16, we changed the consensus parameters for regtest so that segwit was always active. This was mentioned briefly in the release notes <a href="https://github.com/bitcoin/bitcoin/blob/v0.16.0/doc/release-notes.md#testing-changes" rel="nofollow noreferrer">https://github.com/bitcoin/bitcoin/blob/v0.16.0/doc/release-notes.md#testing-changes</a>, along with a workaround to replicate the old behavior.</p>
  
  <p>I am surprised that you're not seeing the assertion failure mentioned in the release notes, but I suspect this is the cause of what you're seeing.</p>
</blockquote>

<p>So this is expected, but only affects regtest.</p>
