When were the 1870 deaf full counts made available?

I thought that I downloaded the deaf data that was available 2 years ago which included:

1850 full count
1860 full count
1870 1.2% sample
1880 10% sample
1910 full count

However, I now see that the deaf variable is available for the 1870 full count census data.
When exactly did this change occur? Did I miss on the first go around?
Is this a question that I can answer on my own? Where would I go to see the answer?

We added DEAF to the 1870 full count data in our recent re-release of the 19th century full count files. Unfortunately, it looks like we failed to document the change. Thank you for bringing this to our attention. Normally, changes such as this are documented in our revision history. We also have a more detailed page describing the changes that were made in the full count data re-release. We will update this documentation to reflect the addition of DEAF and review the documentation to ensure it accurately reflects the full range of updates in the re-release of these files.

Thanks very much!