New appliances - migrating config from 10.2.3 to 11.x

Can I import the config from the old boxes to the new ones and will it convert it as needed?

yes. you may use no-license and no-platform-check options when restoring ucs.

root@(ve11a)(cfg-sync In Sync)(Active)(/Common)(tmos) load sys ucs test.ucs ?
Options:
  include-chassis-level-config  Include chassis level configuration that is shared among boot volume sets.
  no-license                    This option mostly is for RMA use. It loads full configuration from a UCS file except license file.
  no-platform-check             Bypass platform check.
  passphrase                    Passphrase for (un)encrypting UCS.
  reset-trust                   Reset device and trust domain certificates and keys when loading a UCS.

if configuration is missing after restoring, try /usr/libexec/bigpipe daol

Config Transfer 10.1 to 11VE

You may also want to upload a qkview to iHealth, as it will flag features/syntax you may be using currently that are incompatible with v11. The check probably won't catch all possible issues, but it would provide a good starting point.

We just went through the upgrade. Here is what I'd recommend.

1. Create an archive / ucs file.
2. downwnload the recommended hot fix..we used Hotfix-BIGIP-11.4.1-637.0-HF3.iso
3. upload the hotfix to the new F5 and install it, you can use the GUI for this.
4. boot to 11.4.1 and use something like winscp and copy the ucs for to /var/local/ucs
5. from the tmsh issue the following command, load sys ucs ucs_file_name.ucs no-license no-platform-check
6. check the /var/log/ltm file for any install errors. If you have http class profiles check to make sure that local traffic policies have been created.
7. if for some reason you can't log into the box with your configs installed check the managment port's ip, ifconfig, and then add the ip of your laptop. From TMSH, Modify /sys httpd allow add {ip address}
8. If you need to reset the admin password just go to bash utility and issue the command passwd admin. This will prompt you for a new admin account.

After all of that you should be able to log into the device as admin and check all the virtual servers and pools.