Internet Download Manager 6.29 build 1 has been released and added support for Firefox 57 (Firefox Quantum) and Firefox 58 versions.
ICYDK, Tonec is already offering IDM WebExtension for Firefox since 6.28 build 1, and by adding support for upcoming Firefox versions, you can able to download files in Firefox browser using IDM without any issues.
Internet Download Manager 6.29 build 1
IDM 6.29 has added support for https proxy servers, as a result, it’s now possible for you to make VPN connections via https proxy servers by using proxy.pac files.
Tonec has also fixed issues with https downloading via proxy servers with Digest authentication.
You can able to download latest IDM version from their website or if you’re already using IDM, launch it, click check for updates in the Help menu, IDM shows update available, download and install it.