diff --git a/Initialization-options.md b/Initialization-options.md
index e488b89..4cb131f 100644
--- a/Initialization-options.md
+++ b/Initialization-options.md
@@ -15,6 +15,16 @@ This can also be an absolute path. Because the project path is encoded with `@`,
 
 If empty, cache will be stored in memory. Every time a file is re-indexed, the cache will be written to the disk. Use this if you don't want to write cache files.
 
+## `cacheFormat`: serialization format of cache files
+
+Default: `"binary"`, a compact binary serialization format.
+
+Use
+```javascript
+{ "cacheFormat": "json" }
+```
+if you want to inspect the cache file (`IndexFile`), e.g. `jq . < /tmp/ccls/@tmp@c/a.cc.json`
+
 ## `clang.extraArgs` `clang.excludeArgs`
 
 Additional arguments or excluded arguments for `compile_commands.json` entries.
@@ -109,15 +119,15 @@ This is best used in conjunction with empty `cacheDirectory` to avoid writing ca
 }
 ```
 
-## `cacheFormat`: serialization format of cache files
+## `index.trackDependency`
 
-Default: `"binary"`, a compact binary serialization format.
+Default: 2
 
-Use
-```javascript
-{ "cacheFormat": "json" }
-```
-if you want to inspect the cache file (`IndexFile`), e.g. `jq . < /tmp/ccls/@tmp@c/a.cc.json`
+If `a.h` has been changed, when you open `a.cc` which includes `a.h`, an index request will be sent and `a.cc` will be reparsed.
+
+If set to 0, `a.cc` will not be reparsed because its dependencies (included files) have changed timestamps.
+
+1 sits between the two cases: the 2 behavior (default) is used before the initial load while the 0 behavior is used afterwards.
 
 ## `completion.filterAndSort`: completion filtering and sorting