Renewing door bottoms, thresholds and seals

[Friday round]

Happy weekend gents.

My exterior facing doors are over 25 years and need some maintenance. My plan is to
1. replace the threshold part where the rubber has cracked (first two images)
2. replace the door shoes (image 3)
3. update the seals all around the frame (final image)

But I’m a bit lost on where to source replacement parts. Do I try to find like parts and if so, where do I find them? Or is there newer, better designed products now that I should get instead?

Here’s some photos.

 

[crank39]

Looks like an old steel faced door, could be an IG door, might say on the inside of the hinges if you open the door and look, they would be a starting point

 

[ronniecabers]

White door gasket is Qlon and should be readily available on the likes of evilbay , should just pull out so you can try and get dimensions( always tricky as it's not solid lol ).
Bottom of door gasket ... hmm after 25yrs not sure you'll find the original, certainly doesn't look like current IG Doors gasket