GIGABYTE and MSI are the first to announce they are planning BIOS updates for the new CPUs. Despite the Ryzen XT offering no change in terms of core/thread count, cache size, and TDP other than a little clock boost, BIOS updates will optimize system performance.
However, they aren't essential given that the motherboards designed for the Ryzen X-series will fare just fine with the XT variants. Nevertheless, the fact BIOS updates exist suggests they will be worth installing.
The new updates will tap into AMD's new AGESA ComboV2 18.104.22.168 BIOS for X570 and B550 chipset and reportedly boost "compatibility and reliability."
As GIGABYTE explains in a press release published yesterday, "although GIGABYTE motherboards can support 3rd gen AMD Ryzen™ XT series processors without a BIOS update, based on the insistence of providing users better product experiences, GIGABYTE RD started relative verification right after receiving the new BIOS code. With the AMD AGESA ComboV2 22.214.171.124 and ComboV1 126.96.36.199 BIOS update, the compatibility, and reliability between the 3rd gen. AMD Ryzen™ XT series processors and motherboards are enhanced, as well as boosting the performance and overclocking ability of the latest processors."
GIGABYTE is pushing out several BIOS updates for the various chipsets - BIOS version F20 for X570, F2/F3 for the B550, and F51 for the X470, B450, X370, B350, and A320. There are a few exceptions, which you can refer to over on GIGABYTE's website.
As for MSI, the manufacturer plans to push out BIOS updates by the end of June, which will include optimization for the Ryzen 3000 XT chips and 'several key points' and bug fixes.
MSI says, "MSI also made great efforts to offer optimized BIOS updates for 300-, 400-, and 500-series motherboards. The latest AMD Combo PI V1 version 188.8.131.52 BIOS for 300- and 400-series motherboards will be ready for users to download and update at the end of June. Regarding 500-series motherboards, Combo PI V2 version 184.108.40.206 BIOS will be released at the beginning of July. The updated BIOS updates are mainly optimized for the new Ryzen CPUs. Besides, there are several key points for the BIOS improvements."
Given MSI's extensive roster of motherboards, you're best referring to the official announcement over on the company's website for more details.