prob vs but not marked as such in daijs

@@ -17 +16,0 @@
-<misc>&obsc;</misc>

Fine

I think it's similar to how messages sent between embassies and their parent country are called "cables" in English even though they're not actually telegrams (or cablegrams).
Or how congratulatory messages sent between heads of state are still referred to as "祝電" (congratulatory telegram) in Japanese news.
I don't think the original meaning should be marked as obscure so having two senses might be better after all.

@@ -12 +12,5 @@
-<pos>&vs;</pos>
+<gloss>reply telegram</gloss>
+<gloss>answer to a telegram</gloss>
+</sense>
+<sense>
+<pos>&n;</pos>
@@ -14,2 +18 @@
-<gloss>reply (electronic) message (esp. between governments)</gloss>
-<gloss>reply telegram (orig. meaning)</gloss>
+<gloss>(electronic) reply message (sent by a government, head of state, etc.)</gloss>

How's this? 
(Having spent most of my working life in telecoms, including working on the replacement of our telegram system in the 1970s, it strikes me as a little bizarre to have "telegram" as the only gloss for a term that is still in use, albeit rarely.)

@@ -13,8 +13,3 @@
-<gloss>reply (electronic) message</gloss>
-</sense>
-<sense>
-<pos>&n;</pos>
-<pos>&vs;</pos>
-<s_inf>orig. meaning</s_inf>
-<gloss>reply telegram</gloss>
-<gloss>answer to a telegram</gloss>
+<misc>&obsc;</misc>
+<gloss>reply (electronic) message (esp. between governments)</gloss>
+<gloss>reply telegram (orig. meaning)</gloss>

As far as I can tell, all the recent examples refer to official correspondence between heads of state. Not sure it needs to be a separate sense. It's not especially common.