Texture pack version requirement does not match the one used in worlds attempting to be rendered

[Berbe]

I am rendering several worlds with their own version with Overviewer.

However, Overviewer enforces the use of specific texture pack version/branch without caring about what it really needs.

As an example, I got a v1.10.2 world which I would like to render. The server version is used to fetch the proper texture pack (if missing) and the correct version is then correctly fed into overviewer.conf so the Overviewer works with the proper tools.

However, I tried to render my world, and I got this:

Running Overviewer...
Texture path:  ***/textures/1.10.2.jar
overviewer.py:341  8630 2017-03-17 11:13:53 INFO     Welcome to Minecraft Overviewer!
overviewer.py:367  8630 2017-03-17 11:13:53 INFO     Checking all tiles for updates manually.
overviewer.py:477  8630 2017-03-17 11:13:53 INFO     Generating textures...
*******************************************************************************
overviewer.py:612  8630 2017-03-17 11:13:55 ERROR    Could not find the textures while searching for 'assets/minecraft/textures/entity/shulker/shulker_purple.png'. Try specifying the 'texturepath' option in your config file.
Set it to the path to a Minecraft Resource pack.
Alternately, install the Minecraft client (which includes textures)
Also see <http://docs.overviewer.org/en/latest/running/#installing-the-textures>
(Remember, this version of Overviewer requires a 1.11-compatible resource pack)
(Also note that I won't automatically use snapshots; you'll have to use the texturepath option to use a snapshot jar)

Why the hell does Overviewer enforce a specific texture pack version/branch, rather than only failing when a required texture is not found? Stated otherwise, why breaking the following principle?

Require only what is needed

Rendering my world definitely do not need v1.11 branch textures.

[CounterPillow]

Because there is no easy way to implement this, and using a newer texture pack doesn't hurt.

[RikuKawai]

Using a newer texture pack definitely hurts now that 1.12 is the current version.

Rendering worlds from older versions with 1.12 branch textures gives me the new brighter coloured textures for some blocks which I am specifically not playing on 1.12 to avoid.

[CounterPillow]

then use an older overviewer version