I doubt its an issue. When applying for work permits etc...several of these messages are received without any obvious changes in status for you to see but these are usually an indication that your file has been accessed and reviewed in some way. Some of those who got these messages have seen changes in their points etc so the fact that you didn't only means that your file review didn't reveal any need for adjustment and so the update internally could be that your file is ok for whatever the next step is. No need to panic.
Its not age, neither NOC, nor IELTS, its something different.. May be its due to next draw which might happen very soon or may be activation of Job Bank, fingers crossed ;D
Dont worry guys this is normal...once i called cic to ask about it and they said that sometimes when they are just checking your application you will get this message...even if theres no updates at all.