deleted file mode 100644
--- a/mail/config/mozconfigs/linux32/esr
+++ /dev/null
@@ -1,26 +0,0 @@
-ac_add_options --enable-application=mail
-ac_add_options --enable-update-channel=${MOZ_UPDATE_CHANNEL}
-ac_add_options --enable-update-packaging
-ac_add_options --enable-official-branding
-
-# Enable ESR branding
-export MOZ_ESR=1
-
-. $topsrcdir/build/unix/mozconfig.linux
-
-# Avoid dependency on libstdc++ 4.5
-ac_add_options --enable-stdcxx-compat
-
-# Needed to enable breakpad in application.ini
-export MOZILLA_OFFICIAL=1
-
-# For NSS symbols
-export MOZ_DEBUG_SYMBOLS=1
-
-# Enable parallel compiling
-CONCURRENCY=$(( `grep processor /proc/cpuinfo | wc -l` + 2 ))
-mk_add_options MOZ_MAKE_FLAGS="-j$CONCURRENCY"
-
-# Run client.py
-mk_add_options CLIENT_PY_ARGS="$(cat $topsrcdir/build/client.py-args)"
-mk_add_options ALWAYS_RUN_CLIENT_PY=1

deleted file mode 100644
--- a/mail/config/mozconfigs/linux64/esr
+++ /dev/null
@@ -1,26 +0,0 @@
-ac_add_options --enable-application=mail
-ac_add_options --enable-update-channel=${MOZ_UPDATE_CHANNEL}
-ac_add_options --enable-update-packaging
-ac_add_options --enable-official-branding
-
-# Enable ESR branding
-export MOZ_ESR=1
-
-. $topsrcdir/build/unix/mozconfig.linux
-
-# Avoid dependency on libstdc++ 4.5
-ac_add_options --enable-stdcxx-compat
-
-# Needed to enable breakpad in application.ini
-export MOZILLA_OFFICIAL=1
-
-# For NSS symbols
-export MOZ_DEBUG_SYMBOLS=1
-
-# Enable parallel compiling
-CONCURRENCY=$(( `grep processor /proc/cpuinfo | wc -l` + 2 ))
-mk_add_options MOZ_MAKE_FLAGS="-j$CONCURRENCY"
-
-# Run client.py
-mk_add_options CLIENT_PY_ARGS="$(cat $topsrcdir/build/client.py-args)"
-mk_add_options ALWAYS_RUN_CLIENT_PY=1

deleted file mode 100644
--- a/mail/config/mozconfigs/macosx-universal/esr
+++ /dev/null
@@ -1,33 +0,0 @@
-# Big Hack that unsets CC / CXX so that mozconfig.common doesn't get
-# mixed up with host/target CPUs when trying to work out how to do the
-# universal build. When we redo the build system (bug 648979) this will
-# go away.
-if test -e "$topsrcdir/mail/config/version.txt"; then
-  unset CC
-  unset CXX
-fi
-
-. $topsrcdir/build/macosx/universal/mozconfig
-
-# Universal builds override the default of mail (bug 575283 comment 29)
-ac_add_options --enable-application=mail
-ac_add_options --enable-update-channel=${MOZ_UPDATE_CHANNEL}
-ac_add_options --enable-update-packaging
-ac_add_options --enable-official-branding
-
-# Enable ESR branding
-export MOZ_ESR=1
-
-# For NSS symbols
-export MOZ_DEBUG_SYMBOLS=1
-
-# Needed to enable breakpad in application.ini
-export MOZILLA_OFFICIAL=1
-
-# Enable parallel compiling
-CONCURRENCY=$(( `sysctl hw.logicalcpu | awk {'print $2'}`  + 2 ))
-mk_add_options MOZ_MAKE_FLAGS="-j$CONCURRENCY"
-
-# Run client.py
-mk_add_options CLIENT_PY_ARGS="$(cat $topsrcdir/build/client.py-args)"
-mk_add_options ALWAYS_RUN_CLIENT_PY=1

deleted file mode 100644
--- a/mail/config/mozconfigs/win32/esr
+++ /dev/null
@@ -1,24 +0,0 @@
-ac_add_options --enable-application=mail
-ac_add_options --enable-update-channel=${MOZ_UPDATE_CHANNEL}
-ac_add_options --enable-update-packaging
-ac_add_options --enable-jemalloc
-ac_add_options --enable-official-branding
-
-# Enable ESR branding
-export MOZ_ESR=1
-
-# For NSS symbols
-export MOZ_DEBUG_SYMBOLS=1
-
-# Needed to enable breakpad in application.ini
-export MOZILLA_OFFICIAL=1
-
-if test "$PROCESSOR_ARCHITECTURE" = "AMD64" -o "$PROCESSOR_ARCHITEW6432" = "AMD64"; then
-  . $topsrcdir/build/win32/mozconfig.vs2010-win64
-else
-  . $topsrcdir/build/win32/mozconfig.vs2010
-fi
-
-# Run client.py
-mk_add_options CLIENT_PY_ARGS="$(cat $topsrcdir/build/client.py-args)"
-mk_add_options ALWAYS_RUN_CLIENT_PY=1