The BBC reported that France was the first journalist to face trial and be convicted under Operation Elveden since the Crown Prosecution Service (CPS) had revised its guidance in April 2015 so that prosecutions would only be brought against journalists who had made payments to police officers over a period of time. As a result of the change in the CPS’ policy, charges against several journalists who had made payments to other types of public officials – including civil servants, health workers and prison staff - had been dropped. In July 2015, Private Eye magazine reported that at a costs hearing at the Old Bailey The Sun's parent company had refused to pay for the prosecution costs relating to France’s trial, leading the presiding judge to express his "considerable disappointment" at this state of affairs. Judge Timothy Pontius said in court that France’s illegal actions had been part of a "clearly recognised procedure at The Sun", adding that, "There can be no doubt that News International bears some measure of moral responsibility if not legal culpability for the acts of the defendant". The Private Eye report noted that despite this The Sun's parent organisation was "considering disciplinary actions" against France whilst at the same time it was also preparing to bring a case to the Investigatory Powers Tribunal against the London Metropolitan Police Service for its actions relating to him and two other journalists.

Answer this question, if possible (if impossible, reply "unanswerable"): What was the change made to Operation Elveden by the Crown Prosecution Service?
prosecutions would only be brought against journalists who had made payments to police officers over a period of time