Have you tried moving the IBKR app from one smartphone to another? The messages I got that warned me about that this was happening felt so fishy that I initially thought I fell for a scam somehow.
Might be part of their security strategy; fishy communication so that users always check twice no matter whether its legit or not. 
Only problem is, users get used to it.
IBKR sometimes sends official newsletters and system messages by email in which variables are not filled in. So nothing new, I guess 
Here it is the info shown by Postfinance:
Recipientâs account
CH20 8909 5000 0105 6967 4
Recipient bank
Citibank N.A. Canada Square / Canary Wharf E14 5LB London
I redid the same transfer - without the same day option - from Postfinance and it took again 3.5 days to be credited on IBKR (executed on Monday morning, received on Thursday afternoon).
Honestly, it is getting frustating.
Just to confirm, you are with IBKR UK and not IBKR US right?
in my experience of 6 years, the money arrives at IBKR the next day when sent from PostFinance or YUH. The IBAN you mentioned is also what I use, along with a reference text (name, IBKR account ID) in the booking text / reference as shown by IBKR when setting up the transaction to inform them upfront.
Ofc, I am a Swiss resident and I am registered to IBKR UK.
This was my exact same experience until last month.
I will transfer either from Neon or YUH to see the difference.
Just as a FYI, late last night I did exactly the same, initiated the transfer from Postfinance with their (for me new) âQR Billâ generated by IB. A few hours later, at 2am, IB sent an email saying the funds are now available. 
For the record,
I transferred some savings from Yuh on the 05.01 (QR wire) and they showed up only today 07.01.
The transfer notice marks the reception on the 05.01, but the comptabilisation two days later.
I guess IBKR donÂŽt like me for a reason 
Did you send them an ID with photo? 
Check out the settlement delay, it is usually 2 days. Same goes for most type of transactions.
If you want to use the money earlier just change your account to a margin account. You will be charged interest for those two days, but that is really not much.
Hi guys
Once again got the message that some uninvested cash would sit better in moneymarket funds - then I checked the interest rates on usd and chf and saw that they seem to have changed those recently? Back in the day one always got benchmark -0.5% with nav above 100k - did I miss something?
Now it seems they pay way less on small uninvested cash than before?
Money market fund in Switzerland would not yield any positive return at this moment
Itâs still BM - 0.5% for assets over 10k (100k for CHF because theyâre nice and donât want to charge the negative rates)
Postfinance has or had a reputation of holding even domestic transfers for a day to squeeze out a bit of interest.
When transfering from a cantonal bank to the Citibank account until around 13:00, money arrives at IBKR maximum one hour later. Sometimes it barely takes 10 minutes.
Same for Migros Bank. 1 hour max to reach my IBKR account. Even with WIR itâs more or less the same
+1 for UBS.
I issued a transfer 10min ago, and itâs at IBKR now.
Happy DCA day folksđ
-1 for Bank Cler Zak
since 2-3 months they always ask me to confirm over the phone any wire transfers to Swissquote 