If we look at the Espressif ESP-IDF copy of lwip ... we find a VERSION file:
https://github.com/espressif/esp-idf/bl ... ip/VERSION
In that version file we find a Git commit identifier:
bf7fc41e
If we then run "git show bf7fc41e" against the LWIP Git repository, we find that the commit was dated:
March 14th 2016.
So what we can immediately say is that the LWIP apparently being used is likely to be a clone of the LWIP master as of that date. What "numeric release" that pertains to, I'm not sure.
Given that STABLE-2.0.0 was only released 5 weeks ago and that the previous release to that was stable 1.4.1 ... (see here:
http://git.savannah.gnu.org/cgit/lwip.git)
It is possible that the LWIP is approx STABLE-2_0_0_RC1 ... but that's a wild guess.
In your previous post, what is "folder catalog"?
Is there something in a later level of LWIP that you need to take advantage off or a bug fixed?