diff --git a/Projects/AnalysisBase/externals.txt b/Projects/AnalysisBase/externals.txt
index 885e49df41b5433ed5717f0c6f976c2c1d22dd46..b6eea38576bafd3f6c0b9acba3f5ef0d8737405e 100644
--- a/Projects/AnalysisBase/externals.txt
+++ b/Projects/AnalysisBase/externals.txt
@@ -6,5 +6,5 @@
 # forbidden.
 
 # The version of atlas/atlasexternals to use:
-AnalysisBaseExternalsVersion = 5b5c77c6
+AnalysisBaseExternalsVersion = 8643cbb2
 
diff --git a/Projects/AnalysisTop/externals.txt b/Projects/AnalysisTop/externals.txt
index abb5a32e1a2634865378ff55043d5fd76f25b7ec..59f0188418445afd159f1ef525bd38386c52548b 100644
--- a/Projects/AnalysisTop/externals.txt
+++ b/Projects/AnalysisTop/externals.txt
@@ -1,4 +1,4 @@
 # Versions of the various externals to build before starting the build of
 # this project, when doing a full stack nightly build.
 
-AnalysisBaseExternalsVersion = 5b5c77c6
+AnalysisBaseExternalsVersion = 8643cbb2
diff --git a/Projects/AthSimulation/externals.txt b/Projects/AthSimulation/externals.txt
index 5c2b2e7d40a4edc5492b28fddc6bfa0a4a48c04a..c0305844cdf746ce2250ef5980b590b465842a01 100644
--- a/Projects/AthSimulation/externals.txt
+++ b/Projects/AthSimulation/externals.txt
@@ -6,7 +6,7 @@
 # forbidden.
 
 # The version of atlas/atlasexternals to use:
-AthSimulationExternalsVersion = 5b5c77c6
+AthSimulationExternalsVersion = 8643cbb2
 
 # The version of atlas/Gaudi to use:
 GaudiVersion = v28r2.011
diff --git a/Projects/Athena/externals.txt b/Projects/Athena/externals.txt
index e09c9ddfdd56ce096e7566220025bc51224eb336..4a6dd79fc727d1c28b4f2e3be566865e779a2a0c 100644
--- a/Projects/Athena/externals.txt
+++ b/Projects/Athena/externals.txt
@@ -6,7 +6,7 @@
 # forbidden.
 
 # The version of atlas/atlasexternals to use:
-AthenaExternalsVersion = 5b5c77c6
+AthenaExternalsVersion = 8643cbb2
 
 # The version of atlas/Gaudi to use:
 GaudiVersion = v28r2.011