Here's the breakdown:

✅ XMLHttpRequest is still:

• Fully supported by all modern browsers
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• Reliable for handling AJAX requests
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• Capable of handling things like file uploads, form data, custom headers, etc.

🚫 But it is:

• Verbose and more complex (callback-based instead of promise-based)
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• Harder to chain logic (no native then() / catch())
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• Less readable compared to fetch()

✅ Use XMLHttpRequest if:

• You're working on an existing codebase using it
• 
  
• You need fine-grained control over progress events (upload.onprogress, etc.)
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• You're already integrating complex logic like you did with Dropzone and Quill

🔄 Use fetch() if:

• You're writing new code from scratch
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• You want cleaner syntax and async/await support
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• You prefer using Promises

TL;DR:

• Not outdated. Just not modern style.
• 
  
• You don’t need to change it unless you’re refactoring or want Promise-based code.
• 
  
• What you're using is 100% valid — keep using it if it works for your project.

Let me know if you want a direct comparison or how your same code would look with fetch() just for future-proofing.