diff --git a/README.md b/README.md
index 21da3a5..d00954d 100644
--- a/README.md
+++ b/README.md
@@ -115,7 +115,7 @@ For your reference, at the time of writing:
 
 ### Validity for the future
 
-Leap seconds (or the lack thereof) are announced in the International Earth Rotation and Reference Systems Service (IERS)'s six-monthly Bulletin C. For example, at the time of writing, [the latest such bulletin](https://datacenter.iers.org/data/16/bulletinc-068.txt) was published on 4 July 2024 and announced that there will be no leap second at the end of December 2024. This means that `t-a-i`'s calculations are guaranteed to be correct up to, but not including, the *next* potential leap second, which in this case is at the end of June 2025. At or beyond this point, the introduction of leap seconds cannot be predicted in advance, and the correctness of `t-a-i`'s behaviour cannot be guaranteed.
+Leap seconds (or the lack thereof) are announced in the International Earth Rotation and Reference Systems Service (IERS)'s six-monthly Bulletin C. For example, at the time of writing, [the latest such bulletin](https://datacenter.iers.org/data/16/bulletinc-069.txt) was published on 6 January 2025 and announced that there will be no leap second at the end of June 2025. This means that `t-a-i`'s calculations are guaranteed to be correct up to, but not including, the *next* potential leap second, which in this case is at the end of December 2025. At or beyond this point, the introduction of leap seconds cannot be predicted in advance, and the correctness of `t-a-i`'s behaviour cannot be guaranteed.
 
 As a result, `t-a-i`'s behaviour beyond the next-but-one (possible) leap second is considered to be undefined. Updates to the source data when new leap seconds are announced will not be considered breaking changes, and will not incur a major version bump.
 
diff --git a/src/tai-data.js b/src/tai-data.js
index 524a502..31c0d11 100644
--- a/src/tai-data.js
+++ b/src/tai-data.js
@@ -6,12 +6,12 @@ const JAN = 0
 const FEB = 1
 const MAR = 2
 const APR = 3
-const JUN = 5
+// const JUN = 5
 const JUL = 6
 const AUG = 7
 const SEP = 8
 const NOV = 10
-// const DEC = 11
+const DEC = 11
 
 // First column: Unix millisecond count when this relationship became effective
 // Second column: TAI minus UTC in TAI seconds as of the root point
@@ -68,4 +68,4 @@ export const UNIX_START_MILLIS = taiData[0][0]
 // the relationship between Unix time and TAI is unpredictable at or beyond this point.
 // (This is the start of a possible smear.)
 // Updating this value? Don't forget to update the README too!
-export const UNIX_END_MILLIS = Date.UTC(2025, JUN, 30, 12, 0, 0, 0)
+export const UNIX_END_MILLIS = Date.UTC(2025, DEC, 31, 12, 0, 0, 0)