Brew Errorring out

[xaier]

Output of brew config

HOMEBREW_VERSION: 4.3.17
ORIGIN: https://github.com/Homebrew/brew
HEAD: 3426911432b93dc46d20d910c2f4fd33cdac62a2
Last commit: 3 days ago
Core tap HEAD: 2e59a86e8722178d7f51104cba738995b7c476ad
Core tap last commit: 3 years, 10 months ago
Core tap JSON: 01 Jan 08:00 UTC
Core cask tap JSON: 01 Jan 08:00 UTC
HOMEBREW_PREFIX: /usr/local
HOMEBREW_CASK_OPTS: []
HOMEBREW_MAKE_JOBS: 2
Homebrew Ruby: 3.3.4 => /usr/local/Homebrew/Library/Homebrew/vendor/portable-ruby/3.3.4_1/bin/ruby
CPU: dual-core 64-bit penryn
Clang: 8.0.0 build 800
Git: 2.10.1 => /Library/Developer/CommandLineTools/usr/bin/git
Curl: 7.43.0 => /usr/bin/curl
macOS: 10.11.6-x86_64
CLT: 8.2.0.0.1.1480973914
Xcode: N/A

Output of brew doctor

brew doctor
Warning: Using `--insecure` with curl to download formula.jws.json because we need it to run `brew install curl` in order to download securely from now on. Checksums will still be verified.
Warning: Using `--insecure` with curl to download formula_tap_migrations.jws.json because we need it to run `brew install curl` in order to download securely from now on. Checksums will still be verified.
Please note that these warnings are just used to help the Homebrew maintainers
with debugging if you file an issue. If everything you use Homebrew for is
working fine: please don't worry or file an issue; just ignore this. Thanks!

Warning: You have an unnecessary local Core tap!
This can cause problems installing up-to-date formulae.
Please remove it by running:
 brew untap homebrew/core

Warning: You are using macOS 10.11.
We (and Apple) do not provide support for this old version.
It is expected behaviour that some formulae will fail to build in this old version.
It is expected behaviour that Homebrew will be buggy and slow.
Do not create any issues about this on Homebrew's GitHub repositories.
Do not create any issues even if you think this message is unrelated.
Any opened issues will be immediately closed without response.
Do not ask for help from Homebrew or its maintainers on social media.
You may ask for help in Homebrew's discussions but are unlikely to receive a response.
Try to figure out the problem yourself and submit a fix as a pull request.
We will review it but may or may not accept it.


Warning: An outdated version (2.10.1) of Git was detected in your PATH.
Git 2.14.3 or newer is required for Homebrew.
Please upgrade:
  brew install git

Description of issue

keep getting this error: [IMPORTANT] Don't forget to include the Crash Report log file under DiagnosticReports directory in bug reports. Error: Forked child process failed: pid 61297 SIGSEGV (signal 11)

brew install python3
brew update

Yes I know that 10.11 new install isn't supported but if the install was previously working?

[p-linnane]

We have no real ability to test or debug this. El Capitan is the oldest version of macOS Homebrew can run on, but is unsupported so you are unfortunately on your own here unless a community member volunteers to help figure out the issue.