Add mention of enclosure in CHANGES.md

CHANGES.md

@@ -5,6 +5,8 @@ First version of ORS Type B, used for higher frequencies. For now, this type B h
  * 3800Mhz - 4000MHz
  * 4600MHz - 5000MHz
 
+WARNING: this PCB needs a slightly different ORS enclosure.
+
 2023-04-19 (typeA_v4.5)
 -----------------------
 
@@ -60,6 +62,8 @@ The target for this version was to improve the output power.
    we keep the original switch as an option to increase the isolation between the Tx and Rx channels.
  * input voltage range is now 24V-55V (instead of 12V-55V)
 
+Starting from this version, the enclosure is different than previous version.
+
 2020-12-22 (v3.4)
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