I am using an old sony experia at the moment and despite the age of the phone, strava works well.
An option to upgrade has come about and I like the windows phone but there is no strava app for it.
Does anyone use any of the converter style apps, striver et al?

I use Striver, works perfectly well for basic strava-ing but don’t know how it compares to full fat premium Strava.

I used one on a Lumia a couple of years back, can’t remember which one but it was fine. Just a very simple upload client

I’m a basic strava users, so striver might do the trick.

Baika here. Works just like Strava.

Endomondo is a more sophisticated client, and with that one website (forget its name) you can automatically sync between it and Strava, so you can effectively use it as a Strava client.

I use runkeeper, which syncs with the desktop version. Then download the GPX file, and upload it to Strava.