diff --git a/README.md b/README.md
index f22dfc1..4f33386 100644
--- a/README.md
+++ b/README.md
@@ -25,3 +25,17 @@ Use the mounting hole to put stand-off screws, which you have to drill yourself
 The board has a power resistor so to put a heavy load on the 5V output.
 This increases the performance of your ATX power supply (which is a switch mode power supply), so to have better 12V outputs for the light strips.
 A fan (standard 80mm 3-wire PC fan), which you have to connect to the board, will take care of dissipating the generated heat.
+
+versioning
+----------
+
+the version is not defined is the files themselves, but are generated.
+
+for the pcb:
+- use `rake` to generate the outputs
+- is will use the schematic `led-controller.sch`, produced a `led-controller_vX.YYY.sch`, and put the version inside
+- is will use the layout `led-controller.pcb`, produced a `led-controller_vX.ZZZ.pcb`, and put the version inside
+- `X` is the version of the board, defined in `version`
+- version changes are described in `CHANGES.txt`
+- version with letter (A,B,C,…) are releases, version with number (0,1,2,…) are intermediate working stages
+- `YYY` and `ZZZ` are revisions, independent of the version and each other. they described how often the schematic/layout has been modified (git commits)