Since there is not an in-place upgrade option at this point, getting to cDOT from a 2240 will require either swing gear or a hardware refresh. Depending on where you are in the systems lifecycle a hardware refresh may or may not be on the horizon. But there is plenty you can do now to help align yourself for a smooth transition.
Here is what I would suggest:
-Update to 8.1.4P9. Why? Because 32bit data, including old snapshots, can't be brought forward into 8.3+. Capabilities were added at 8.1.4P4 to identify 32bit snapshot data, so you'll often see transition related tools that require 8.1.4P4 or later. Get started now converting any 32bit aggregates to 64bit so old snaps can start to age out. Its also a good release to be on while you plan the next round of upgrades.
-Install 7MTT and use the "Collect & Assess" to spot feaatures and settings you may not be using that show up on the precheck list in the transition workbook. Start aligning your configuration now for a smooth transition later.
-Plan an upgrade to a current release of 8.2. A lot has happened since 8.1. All the SM* software, snapdrives, host utilities kits etc have continued to evolve and will need to be updated as you upgrade to 8.2+. Use the interoperability matrix tool (IMT) to identify the supported versions required as you mature your code revs. When the time comes to look at an 8.3 transition you should have an easier time finding versions that work accross the 8.2/8.3 release families.
-Learn all about cDOT. Take advantage of the WBTs and update your skills.
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