diff --git a/readme-build.md b/readme-build.md
index 12668ce..27517c3 100644
--- a/readme-build.md
+++ b/readme-build.md
@@ -31,8 +31,8 @@ You probably want to create an alias for qmake, like:
 alias qmake='<path-to-qt>/<compiler>/bin/qmake'
 ```
 
-Please make sure you have both latest **ECL** (from development branch) and
-either **Qt5.15** or **Qt6** installed (see [readme-qt](readme-qt.md)).
+Please make sure you have both **ECL 23.9.9** and either **Qt5.15** or **Qt6**
+installed (see [readme-qt](readme-qt.md)).
 
 ```
 $ cd src/build
diff --git a/readme-prepare-android.md b/readme-prepare-android.md
index 60fd967..5a234b2 100644
--- a/readme-prepare-android.md
+++ b/readme-prepare-android.md
@@ -41,10 +41,10 @@ Build cross-compiled ECL for android
 ------------------------------------
 
 To build the cross-compiled ECL **aarch64**, just use the 2 scripts included in
-this project. As of March 2022, please use latest ECL from development branch.
+this project. You'll need latest ECL 23.9.9.
 
 * extract a fresh copy of the ECL sources in e.g. `~/ecl`, and rename
-  `ecl-21.2.1` to `android`
+  `ecl-23.9.9` to `android`
 * copy the 2 scripts from [platforms/android/build-ecl/](platforms/android/build-ecl/)
   to `~/ecl/android/`
 * run both scripts in order
diff --git a/readme-prepare-ios.md b/readme-prepare-ios.md
index 68ac358..ad06ae6 100644
--- a/readme-prepare-ios.md
+++ b/readme-prepare-ios.md
@@ -15,7 +15,7 @@ immediately in your current terminal session.)
 Build cross-compiled ECL for iOS
 --------------------------------
 
-As of May 2023, please use latest ECL from development branch.
+You'll need ECL 23.9.9.
 
 **Important**: pay attention to file `src/c/unixsys.d`, function `si_system()`.
 Function `system()` inside of it needs to work when running script **1**, and
@@ -46,7 +46,7 @@ si_system(cl_object cmd_string)
 ```
 
 * extract a fresh copy of the ECL sources in e.g. `~/ecl`, and rename
-  `ecl-21.2.1` to `ios`
+  `ecl-23.9.9` to `ios`
 * copy the 2 scripts from [platforms/ios/build-ecl/](platforms/ios/build-ecl/)
   to `~/ecl/ios/`
 * run first script