want Job Stock template for my Tennnis related site

Hello everyone,

I have a site related to Tennis Racquets https://gotennisracquets.com, and I want to Subdomamin related to only for Tennis courts, I liked this theme https://themeforest.net/item/job-stock-job-board-template/20356743 but it’s in “Bootstrap 3.x”.
I will buy this theme if anyone can covert this in “Bootstrap 4.x”, any support team can help me in this matter?

Thankx in Advance…