diff --git a/IMPACT.md b/IMPACT.md
index e8430ab5..6d963a34 100644
--- a/IMPACT.md
+++ b/IMPACT.md
@@ -18,6 +18,8 @@ For Impact 4.3, there is no Baritone integration yet, so you will want `baritone
 
 Any official release will be GPG signed by leijurv (44A3EA646EADAC6A) and ZeroMemes (73A788379A197567). Please verify that the hash of the file you download is in `checksums.txt` and that `checksums_signed.asc` is a valid signature by those two public keys of `checksums.txt`. 
 
+The build for `baritone-unoptimized-X.Y.Z.jar` is deterministic, and you can verify Travis did it properly by running `scripts/build.sh` yourself and comparing the shasum. The proguarded files (api and standalone) aren't yet reproducible, because proguard annoyingly includes the current timestamp into the final jar.
+
 ### Building Baritone yourself
 There are a few steps to this
 - Clone this repository