I had an offline wallet of version 1.9.8. Yesterday i tryed to spend some of my BTC and got a message
"your wallet created a transaction which is no longer accepted by bitcoin network, you need to upgrade to 2.5.x" .i tried to broadcast a transaction several times same message!
What is last version stable ? for (Win XP) OS I prefer to use.
What is upgrade steps? thank you in advance.
You need to upgrade both the offline and the online wallet.
#1 download
https://electrum.org/#download & verify
#2 transfer to offline system
#3 install
#4 start
#5 if needed (you should not have to) restore from seed.