Bump version to 1.7.0

Change-Id: I5e7a655e8af44f893905760b5fbd6fd70c2d48ea
diff --git a/CMakeLists.txt b/CMakeLists.txt
index bfdcca0..15ad178 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,5 +1,5 @@
 cmake_minimum_required(VERSION 3.9)
-project(collocatordb VERSION 1.6.0 DESCRIPTION "Storing and retrieving collocation counts based on RocksDB")
+project(collocatordb VERSION 1.7.0 DESCRIPTION "Storing and retrieving collocation counts based on RocksDB")
 set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -g -fno-rtti")
 set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -g")
 
diff --git a/README.md b/README.md
index acf0672..a5c5edb 100644
--- a/README.md
+++ b/README.md
@@ -193,6 +193,16 @@
 
 ## Changes
 
+* v1.7.0 (2026-08-09)
+  * single-key increments are collected in a batch and written in one rocksdb
+    write per batch, instead of one write per increment. The batch size can be
+    set with `COLLOCATORDB_BATCH_SIZE` (default 65536), and the whole run can be
+    tuned from the environment, see above. A write is done without holding the
+    collection lock, so the other indexing threads keep counting while it is in
+    flight, which makes the indexer faster with more than one thread. A read
+    writes out what is still in the batch first, so it sees every increment
+    that came before it
+
 * v1.6.0 (2026-08-02)
   * fixed the loss of increments: rocksdb was told to cancel a write instead of
     waiting when compaction is behind, and the result was not looked at. Under