diff --git a/scripts/bump_version.sh b/scripts/bump_version.sh
index 64af2dcbb..d419f1c10 100755
--- a/scripts/bump_version.sh
+++ b/scripts/bump_version.sh
@@ -46,17 +46,17 @@ then
 fi
 
 [ $VERBOSE ] && echo "Bumping VERSION in library/CMakeLists.txt"
-sed -e "s/ VERSION [0-9.]\+/ VERSION $VERSION/g" < library/CMakeLists.txt > tmp
+sed -e "s/ VERSION [0-9.]\{1,\}/ VERSION $VERSION/g" < library/CMakeLists.txt > tmp
 mv tmp library/CMakeLists.txt
 
 if [ "X" != "X$SOVERSION" ];
 then
   [ $VERBOSE ] && echo "Bumping SOVERSION in library/CMakeLists.txt"
-  sed -e "s/ SOVERSION [0-9]\+/ SOVERSION $SOVERSION/g" < library/CMakeLists.txt > tmp
+  sed -e "s/ SOVERSION [0-9]\{1,\}/ SOVERSION $SOVERSION/g" < library/CMakeLists.txt > tmp
   mv tmp library/CMakeLists.txt
 
   [ $VERBOSE ] && echo "Bumping SOVERSION in library/Makefile"
-  sed -e "s/SOEXT=so.[0-9]\+/SOEXT=so.$SOVERSION/g" < library/Makefile > tmp
+  sed -e "s/SOEXT=so.[0-9]\{1,\}/SOEXT=so.$SOVERSION/g" < library/Makefile > tmp
   mv tmp library/Makefile
 fi
 
@@ -64,23 +64,23 @@ fi
 read MAJOR MINOR PATCH <<<$(IFS="."; echo $VERSION)
 VERSION_NR="$( printf "0x%02X%02X%02X00" $MAJOR $MINOR $PATCH )"
 cat include/polarssl/version.h |                                    \
-    sed -e "s/_VERSION_MAJOR .\+/_VERSION_MAJOR  $MAJOR/" |    \
-    sed -e "s/_VERSION_MINOR .\+/_VERSION_MINOR  $MINOR/" |    \
-    sed -e "s/_VERSION_PATCH .\+/_VERSION_PATCH  $PATCH/" |    \
-    sed -e "s/_VERSION_NUMBER .\+/_VERSION_NUMBER         $VERSION_NR/" |    \
-    sed -e "s/_VERSION_STRING .\+/_VERSION_STRING         \"$VERSION\"/" |    \
-    sed -e "s/_VERSION_STRING_FULL .\+/_VERSION_STRING_FULL    \"mbed TLS $VERSION\"/" \
+    sed -e "s/_VERSION_MAJOR .\{1,\}/_VERSION_MAJOR  $MAJOR/" |    \
+    sed -e "s/_VERSION_MINOR .\{1,\}/_VERSION_MINOR  $MINOR/" |    \
+    sed -e "s/_VERSION_PATCH .\{1,\}/_VERSION_PATCH  $PATCH/" |    \
+    sed -e "s/_VERSION_NUMBER .\{1,\}/_VERSION_NUMBER         $VERSION_NR/" |    \
+    sed -e "s/_VERSION_STRING .\{1,\}/_VERSION_STRING         \"$VERSION\"/" |    \
+    sed -e "s/_VERSION_STRING_FULL .\{1,\}/_VERSION_STRING_FULL    \"mbed TLS $VERSION\"/" \
     > tmp
 mv tmp include/polarssl/version.h
 
 [ $VERBOSE ] && echo "Bumping version in tests/suites/test_suite_version.data"
-sed -e "s/version:\".\+/version:\"$VERSION\"/g" < tests/suites/test_suite_version.data > tmp
+sed -e "s/version:\".\{1,\}/version:\"$VERSION\"/g" < tests/suites/test_suite_version.data > tmp
 mv tmp tests/suites/test_suite_version.data
 
 [ $VERBOSE ] && echo "Bumping PROJECT_NAME in doxygen/mbedtls.doxyfile and doxygen/input/doc_mainpage.h"
 for i in doxygen/mbedtls.doxyfile doxygen/input/doc_mainpage.h;
 do
-  sed -e "s/mbed TLS v[0-9\.]\+/mbed TLS v$VERSION/g" < $i > tmp
+  sed -e "s/mbed TLS v[0-9\.]\{1,\}/mbed TLS v$VERSION/g" < $i > tmp
   mv tmp $i
 done