Cisco – Copy Software from on IOS-Device to another

I have 3 Aironet Access Points.

2 are running on Version 15.3(3)JBB1 and when I factory resetted and its actually running on Version 15.2(4)JB3a.

I wanted to copy the Configuration of on of the AP to the resetted one. But they are not on the same software and I think, this is the reason why i don't work right.

We don't have an active contract (I asked) with Cisco. Is it possible to get the Image from one AP to another? And which file is it?

Here's the output of the flash:

AP#show flash: 

Directory of flash:/

    2  -rwx           4   Sep 4 2015 14:32:44 +00:00  FOC17304FJT
    3  -rwx         405   Mar 1 1993 00:00:19 +00:00  env_vars
   44  drwx         768  Jul 31 2013 06:41:27 +00:00  c1140-k9w7-mx.153-3.JBB1
    5  -rwx        9010  Jul 31 2013 06:41:33 +00:00  event.log
    4  -rwx        2572  Dec 10 2015 14:18:02 +00:00  private-config
    7  drwx         128  Jul 31 2013 06:37:10 +00:00  c1140-rcvk9w8-mx
   43  drwx           0  Jul 31 2013 06:38:16 +00:00  configs
    6  -rwx        5182  Dec 10 2015 14:18:02 +00:00  config.txt
   10  -rwx        7192  Dec 10 2015 14:18:02 +00:00  private-multiple-fs

c1140-k9w7-mx.153-3.JBB1 is a fodler where I think the image is stored. But I need a tar file (for upgrading with gui).

What should I do? Are isn't it possible to upgrade the one AP and i have to stay at 15.2 with this one.

UPDATE1:

AP#copy flash:/c1140-k9w7-mx.153-3.JBB1/c1140-k9w7-xx.153-3.JBB1 ftp://ftpuser:ftppassword@IP//home/upload/
Address or name of remote host [IP]? 
Destination filename [/home/upload/c1140-k9w7-xx.153-3.JBB1]? 
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
7954956 bytes copied in 7.184 secs (1107316 bytes/sec)

But it isn't there:

ls -la /home/upload/
insgesamt 28
drwxr-xr-x 2 ftpuser ftpuser 4096 Apr  5 15:45 .
drwxr-xr-x 5 root    root    4096 Apr  5 11:59 ..
-rw-r--r-- 1 ftpuser ftpuser  220 Apr  5 11:59 .bash_logout
-rw-r--r-- 1 ftpuser ftpuser 3515 Apr  5 11:59 .bashrc
-rw-r--r-- 1 root    root    5015 Apr  5 13:46 config.txt
-rw-r--r-- 1 ftpuser ftpuser  675 Apr  5 11:59 .profile

UPDATE2: show Flash on resetted AP

AP2#show flash: 

Directory of flash:/

    2  -rwx        1892   Mar 1 1993 00:16:52 +00:00  event.log
    3  -rwx        1909   Apr 5 2016 12:51:55 +00:00  private-config
    4  -rwx        3096   Apr 5 2016 12:51:55 +00:00  private-multiple-fs
    5  drwx        2048   Jan 1 1970 00:00:03 +00:00  ap1g1-k9w7-mx.152-4.JB3a
  198  -rwx         286   Mar 1 1993 01:14:07 +00:00  env_vars
  199  -rwx        5425   Apr 5 2016 12:51:55 +00:00  config.txt

131334144 bytes total (118214656 bytes free)