The European Commission is set to launch an appeal against a recent decision by the European Union General Court in favor of Apple (AAPL  ). The decision overturned a previous decision that Apple had been given illegal tax breaks by the Irish government.

The E.U. General Court ruled in favor of Apple, going against the European Commission and its claims that Apple had received a special deal with the Irish government that the Commission argued would allow it to avoid E.U. taxes on revenue. The court ruling, which was issued in July, found that the Commission didn't present enough evidence to prove their point.

"The commission did not succeed in showing to the requisite legal standard that there was an advantage...the commission did not prove, in its alternative line of reasoning, that the contested tax rulings were the result of discretion exercised by the Irish tax authorities." The ruling said.

The ruling is set to be appealed by the Commission, which is hoping that an earlier decision by an E.U. antitrust judge will be reaffirmed. Said judge has since spoken up in support of the Commission's appeal, going so far as to say that the General Court "has made numerous errors of law."

"The General Court has repeatedly confirmed the principle that, while Member States have competence in determining their taxation laws taxation, they must do so in respect of E.U. law, including State aid rules. If Member States give certain multinational companies tax advantages not available to their rivals, this harms fair competition in the European Union in breach of State aid rules," said the judge.

The battle between the European Commission and Apple over the latter's tax status has been raging since 2014. Apple, like many companies, prefers operating in Ireland for its low tax rate. On top of the low tax rate, Apple was allegedly receiving preferential treatment, receiving a tax rate of around 1%. The European Commission launched a probe that later found that Apple owed Ireland a whopping €12.5 billion (approx. $14.5 billion). A protracted legal battle erupted, with Apple and the Commission battling one another in the E.U. legal system in a fight that has lasted six years. With the latest appeal, the case will now move up the European legal system totem pole to the European Court of Justice.