In what's rapidly becoming a long-running saga, Apple seems to have admitted there is a problem with iPhone 4 reception. But the leaked memo received at Boy Genius Report also claims the issue is far wider than the iPhone 4.The document concerned, distributed to AppleCare staff, is the company's official response to the antenna issue that has dogged the phone since launch. It states that there is a problem with the iPhone 4, but it's a problem that affects more than Apple'a latest smartphone. Or as the document reads: 'Gripping almost any mobile phone in certain places will reduce its reception. This is true of the iPhone 4, the iPhone 3GS, and many other phones we have tested. It is a fact of life in the wireless world.'With that in mind, it would seem that the software upgrade talked up earlier this week is no going to remove the problem completely. So how is the problem best avoided? Well, Apple has a solution of sorts ready to go.According to the leaked document: 'If you are experiencing this on your iPhone 4, avoid covering the black strip in the lower-left corner of the metal band.' Apple adds that: 'The use of a case or bumper that is made out of rubber or plastic may improve wireless performance by keeping your hand from directly covering these areas.'Oh yes, the bumper. Not free though, the document instructs staff not to make a promise of 'free bumpers', even though this could solve the problem. If you want one, that'll be £25, which is probably going to leave a sour taste when the problem is not of your doing.