error: xdr processing error: xdr value invalid | Bug Report

[Stellar-tickets]

as reported here in discord: https://discord.com/channels/897514728459468821/966788672164855829/1240783985370595429

you can't invoke hello world from 20.3.4 on testnet
maybe we need to use v21 for p21?
Hey guys I'm p[robably doing something wrong.
I deploy it, it returns the contract key, but I can't invoke

soroban contract deploy
--wasm target/wasm32-unknown-unknown/release/hello_world.wasm
--source bob
--network testnet
CA2PGFVXARVLBJHITPJLCMTKL2VNO32HYUES5RJRT3CHK35IOFDPG2S6
soroban-hello-world soroban contract invoke
--id CA2PGFVXARVLBJHITPJLCMTKL2VNO32HYUES5RJRT3CHK35IOFDPG2S6
--source bob
--network testnet
--
hello
--to RPC
error: xdr processing error: xdr value invalid

[Stellar-tickets]

🔗 Discuss this issue on Discord

[willemneal]

I can confirm that I was able to invoke with soroban 21.0.0-preview.1, so my guess is that the XDR was updated and now the old version doesn't work. Though I thought it was supposed to be backward compatible @leighmcculloch

[leighmcculloch]

XDR is backwards compatible (network v20 producing data understandable by consumer CLI v21) but not forwards compatible (network v21 producing data understandable by consumer CLI v20), which I think is what's happening here. Anyone consuming data from testnet v21 needs CLI v21, and CLI v20 may see issues decoding XDR. Going to close this issue in light of that, but feel free to reopen if not.