OpenWrt openSSL issue

I have an app based on openSSL. The app was designed in openWRT 18.06. Now I have upgrade the openWRT version to 19.07. But openSSL version also got updated. Can any please how to downgrade openSSL version from 1.1.1i to 1.0.2h. Thank you

probably a lot easier to downgrade openwrt back to 18.06, then to try to fix the openSSL.

Thank you for reply @frollic . The app is working fine with openWRT 18.06 and openssl 1.0.2h.