You are in luck.
Latest version for 10.11 is 3.3.8. You can see on internet archive that 3.3.8 was 10.11 and 4.0.4 was 10.13.
I'm saying that you're in luck because versions older than 3.3.4 should not be used, but 3.3.8 is fine.
I have the download folder too for you: https://download.electrum.org/3.3.8/