Hey there! Let's clear up the jQuery compatibility for Bootstrap, starting with your specific question about Bootstrap 4.0.0.

Bootstrap 4.0.0 requires jQuery 1.9.1 or newer — and while it works with older jQuery 2.x versions, the recommended pick is a jQuery 3.x release (like 3.2.1 or later) since that was the stable, mainstream branch at the time Bootstrap 4.0.0 launched. Avoid super old jQuery versions (pre-1.9.1) because they lack some APIs Bootstrap relies on.

Here's a breakdown of all compatible version pairs for reference:

Bootstrap 3.x Series #

• Bootstrap 3.0.x to 3.3.x: Works with jQuery 1.9.1+ (includes 2.x and 3.x branches). Early jQuery 3.0 releases had minor quirks, but any 3.x version after that is fully supported.

Bootstrap 4.x Series #

• Bootstrap 4.0.0: jQuery 1.9.1+ (recommended: jQuery 3.2.1+)
• Bootstrap 4.1.x to 4.6.x: Still requires jQuery 1.9.1+, but official docs recommend jQuery 3.4.1+ for better compatibility and bug fixes.

Bootstrap 5.x Series #

• Critical note: Bootstrap 5 completely removes jQuery dependency! All components are rewritten in vanilla JavaScript, so you don't need jQuery at all for Bootstrap 5 projects.

Bootstrap 2.x Series (Legacy, for reference only) #

• Bootstrap 2.0.x to 2.3.x: Compatible with jQuery 1.7.x up to 1.11.x. Not recommended for new projects due to outdated features and security concerns.

• Always load jQuery before Bootstrap's JavaScript file — if you do it the other way around, Bootstrap's plugins (modals, dropdowns, etc.) won't initialize properly.
• Stick to the recommended jQuery version for your Bootstrap release to avoid unexpected bugs (like broken event handlers or misbehaving components).

内容的提问来源于stack exchange，提问作者user9614988