diff --git a/CHANGELOG.md b/CHANGELOG.md
index 731b5301dd6908cc1423d190a2352687f7ac04f4..33568e14767255330a402acb20cf3d58ce257003 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,7 +1,12 @@
 # libaec Changelog
 All notable changes to libaec will be documented in this file.
 
-## [1.1.0] - 2023-08-21
+## [1.1.1] - 2023-09-29
+
+### Fixed
+- Offsets when encoding by Eugen Betke
+
+## [1.1.0] - 2023-08-21 (not released)
 
 ### Changed
 - Rename aec executable to graec. This avoids a name clash with the
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 2fe3a9470d26f62840a7b72cd47a1c4d907d62c9..45f75bb6f182f5a7695578923ea2de437bf2335f 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,5 +1,5 @@
 cmake_minimum_required(VERSION 3.13...3.19)
-project(libaec LANGUAGES C VERSION 1.1.0)
+project(libaec LANGUAGES C VERSION 1.1.1)
 
 # Automatically export symbols for Windows DLLs
 set(CMAKE_WINDOWS_EXPORT_ALL_SYMBOLS TRUE)
diff --git a/INSTALL.md b/INSTALL.md
index 4715ceb2dda49d84e8f5f20a9e64873a18540839..13402d412a124dfc2400029771145b493ba9c9dd 100644
--- a/INSTALL.md
+++ b/INSTALL.md
@@ -85,11 +85,16 @@ generate it with autotools and gnulib:
   make check install
 ```
 
-# Intel compiler settings
+# Optimization
 
-The Intel compiler can improve performance by vectorizing certain
-parts of the code on x86 architectures. Assuming your CPU supports
-AVX2, the following options will increase encoding speed.
+Libaec in general and encoding performance in particular can benefit
+from vectorization and other compiler optimizations. You can try to
+enable higher than default optimizations and check the benefits with
+the bench target.
+
+## Intel compiler
+Assuming your CPU supports AVX2, the following options will increase
+encoding speed.
 
 ```shell
   ../configure CC=icc
@@ -99,4 +104,6 @@ AVX2, the following options will increase encoding speed.
 On a 3.4 GHz E3-1240 v3 we see more than 400 MiB/s for encoding
 typical data.
 
-Using other SIMD instruction sets on older CPUs may also help.
+## gcc
+The default -O2 will already enable vectorization but -O3 yields even
+better performance.
diff --git a/configure.ac b/configure.ac
index afafb49da5e4824a15eedc99be8a7d7a17932b9f..32968f9bdd9f97d7431499646cdb0e70736219b1 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1,10 +1,10 @@
-AC_PREREQ([2.64])
+AC_PREREQ([2.71])
 
 m4_define([VERSION_MAJOR], [1])
 m4_define([VERSION_MINOR], [1])
-m4_define([VERSION_PATCH], [0])
+m4_define([VERSION_PATCH], [1])
 
-AC_INIT([libaec], [VERSION_MAJOR.VERSION_MINOR.VERSION_PATCH], [rosenhauer@dkrz.de])
+AC_INIT([libaec],[VERSION_MAJOR.VERSION_MINOR.VERSION_PATCH],[rosenhauer@dkrz.de])
 
 AC_SUBST(PROJECT_VERSION_MAJOR, [VERSION_MAJOR])
 AC_SUBST(PROJECT_VERSION_MINOR, [VERSION_MINOR])
@@ -20,9 +20,7 @@ gl_VISIBILITY
 AM_INIT_AUTOMAKE([foreign])
 AM_MAINTAINER_MODE([enable])
 
-AC_PROG_CC_C99
-
-AC_HEADER_STDC
+AC_PROG_CC
 
 AC_C_BIGENDIAN
 AC_C_INLINE
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 4c7fbfbc4ce4faf35d10f91f28f57958c0a65850..8a26e8fbe8835407765de5f27e06004b38eabe66 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -22,7 +22,7 @@ add_library(aec_shared SHARED "$<TARGET_OBJECTS:aec>")
 target_link_libraries(aec_shared PUBLIC aec)
 set_target_properties(aec_shared
   PROPERTIES
-  VERSION 0.1.0
+  VERSION 0.1.1
   SOVERSION 0
   OUTPUT_NAME aec
   PUBLIC_HEADER ${CMAKE_CURRENT_BINARY_DIR}/../include/libaec.h)
diff --git a/src/Makefile.am b/src/Makefile.am
index be452d47575f631d1d7c58ed1ffe1b43b9aadf90..50ee18b5d0b7105c613505dd3f1e4bc52117118e 100644
--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -5,7 +5,7 @@ AM_CPPFLAGS = -I$(top_srcdir)/include -I$(top_builddir)/include \
 lib_LTLIBRARIES = libaec.la libsz.la
 libaec_la_SOURCES = encode.c encode_accessors.c decode.c vector.c\
 encode.h encode_accessors.h decode.h vector.h
-libaec_la_LDFLAGS = -version-info 1:0:1 -no-undefined
+libaec_la_LDFLAGS = -version-info 1:1:1 -no-undefined
 
 libsz_la_SOURCES = sz_compat.c
 libsz_la_LIBADD = libaec.la