It's only the bc1 addresses that won't work backwards compatibly, and that's kind of irrelevant seeing as there aren't many wallets that use bc1 addresses.
Best advice is to use nested 3-starting addresses for Segwit now, because they're completely backwards compatible for all services and wallets. So there's no need to wait for others to wait to update, you can use Segwit now backwards compatibly.
You seem to confuse the meaning of backwards compatibility.
Bech32 addresses are backwards compatible.
This means:
- Transactions between legacy and bech32 addresses are compatible.
- "Old" nodes do "understand" those transactions from/to bech32 addresses
- There aren't any (network-)problems with bech32.
Wallets/Exchanges/Online service provider not accepting bech32 yet is due to not upgraded software (non-network related).
This has nothing to do with backwards compatibility. They just didn't update the software to accept those addresses.
Older software will refuse to send to bc1 addresses, as a basic error-checking measure.
I heard that coinbase, an exchange that I use when I need to cash out some coins, is finally going to update to segwit. I have no idea what type of addresses they will be using. But since they are updating to segwit, does this mean that even if they use the P2SH I will be able to make transfer to them if I use the bech32 addresses from electrum?
You can send
from P2SH segwit or bech32/bc1 addresses now. It's sending
to segwit addresses from non-upgraded exchanges that's the issue.