Excellent - Thanks for your response Jorge. This helps us plan out the future upgrades properly.
Since I see 0.15 and 0.16 use block versions as 0x20000000, whereas the current deployed codebase (based on bitcoin 0.9.4) makes versions 0x00000002 (as seen by a 0.15 client), it appears safe to activate soft forks which require a minimum of version 3 and 4 blocks (0x00000003 and 0x00000004, respectively). Would you agree?

On Wed, Mar 28, 2018 at 7:55 AM, Jorge Timón <jtimon@jtimon.cc> wrote:
Yes, you can activate softforks at a given height.
I don't see any reason why you couldn't rebase to 0.16 directly.
The block version bumping was a mistake in bip34, you don't really
need to bump the version number. In any case, I would recommend
reading bip34 and what it activates in the code. IIRC the last thing
was bip65.

On Wed, Mar 21, 2018 at 11:04 PM, Samad Sajanlal via bitcoin-dev
<bitcoin-dev@lists.linuxfoundation.org> wrote:
> Is it possible to activate soft forks such as BIP65 and BIP66 without prior
> signaling from miners? I noticed in chainparams.cpp that there are block
> heights where the enforcement begins.
>
> I understand this is already active on bitcoin. I'm working on a project
> that is a clone of a clone of bitcoin, and we currently do not have BIP65 or
> BIP66 enforced - no signaling of these soft forks either (most of the
> network is on a source code fork of bitcoin 0.9). This project does not and
> never intends to attempt to replace bitcoin - we know that without bitcoin
> our project could never exist, so we owe a great deal of gratitude to the
> bitcoin developers.
>
> If the entire network upgrades to the correct version of the software (based
> on bitcoin 0.15), which includes the block height that has enforcement, can
> we simply skip over the signaling and go straight into
> activation/enforcement?
>
> At this time we are lucky that our network is very small, so it is
> reasonable to assume that the whole network will upgrade their clients
> within a short window (~2 weeks). We would schedule the activation ~2 months
> out from when the client is released, just to ensure everyone has time to
> upgrade.
>
> We have been stuck on the 0.9 code branch and my goal is to bring it up to
> 0.15 at least, so that we can implement Segwit and other key features that
> bitcoin has introduced. The 0.15 client currently works with regards to
> sending and receiving transactions but the soft forks are not active. I
> understand that activating them will segregate the 0.15 clients onto their
> own fork, which is why I'd like to understand the repercussions of doing it
> without any signaling beforehand. I also would prefer not to have to make
> intermediate releases such as 0.10, 0.11.. etc to get the soft forks
> activated.
>
> Another related question - does the block version get bumped up
> automatically at the time that a soft fork activates, or is there additional
> stuff that I need to do within the code to ensure it bumps up at the same
> time? From what I saw in the code it appears that it will bump up
> automatically, but I would like some confirmation on that.
>
> Regards,
> Samad
>
>
>
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