Any approach to determine the filename on server side?

Referring to following PHP script, the previous one is probably no longer work after the change at the start of last year from bin to bi5.

I would like to sort it out, but it seems impossible to access the data without knowing the correct bi5 filename format.  Is anyone able to sort out what filename format they use? I have tried following code without luck.
Does anyone have any suggestions?

Thanks you very much for any suggestions

Previous version worked before changed, once it changes from bin to bi5, they are no longer working

File to download : http://sdrv.ms/17FwXEF

        $askurl = "http://www.dukascopy.com/datafeed/$pair/$year/$month/$day/ASK_candles_$candletype.bin";
        $bidurl = "http://www.dukascopy.com/datafeed/$pair/$year/$month/$day/BID_candles_$candletype.bin";
        //error("Info: Processing $pair $i - ".gmstrftime("%D %T",$i)." --- $url\n");
        $localpath = "$pair/$year/$month/$day/";
        $asklocalfile = $localpath . "ASK_candles_$candletype.bin";
        $bidlocalfile = $localpath . "BID_candles_$candletype.bin";

Current version is working

File to download : http://sdrv.ms/13UdlKZ

        $url = "http://www.dukascopy.com/datafeed/$pair/$year/$month/$day/{$hour}h_ticks.bi5";
        //error("Info: Processing $pair $i - ".gmstrftime("%m/%d/%y %H:%M:%S",$i)." --- $url\n");
        $localpath = "$pair/$year/$month/$day/";
        $binlocalfile = $localpath . $hour . "h_ticks.bin";
        $localfile = $localpath . $hour . "h_ticks.bi5";

Thanks in advance for any suggestions