Availability in the single race variable (racesing) in the ACS

I would like to use racesing variable for the 2019 ACS, but I noticed that it is only available up until 2014. Is there any particular reason why it is not available for the 2019 ACS? Thank you for your support!

The RACESING variable was constructed from a variety of data sources, not just the Census microdata. As such, it is not simple to calculate this variable for new samples. However you can use the “race bridge” code linked on the RACESING variable description page to assign a single race category to individuals in later ACS samples, though it will not perfectly replicate the values of RACESING. The IPUMS USA team is currently working on developing a new variable that will supercede RACESING and will be available for all samples. This should be released sometime next year.