Thank you for asking this question in the support community forum. When upgrading AOS firmware from a version prior to 18.03.00/R10.1.0, to a version of AOS 18.03.00/R10.1.0 or later, the newer AOS version will auto-change the configuration to adhere to the new BGP commands; therefore, you do not need to change any commands manually. Please, note, the opposite does not work (i.e. if you downgrade AOS from the current AOS BGP commands, to a version prior to 18.03.00/R10.1.0, the BGP commands will not be compatible).
Here is the Configuring BGP in AOS Releases Prior to 18.03.00/R10.1.0 guide and here is the Configuring BGP in AOS 18.03/R10.1.0 or later guide. I hope that makes sense, but please do not hesitate to reply to this post with any additional information or questions. I will be happy to help in any way I can.