Roll-up 4 for Microsoft Dynamics AX 2009 RTM and SP1 is now available on PartnerSource and CustomerSource.
There will be one roll-up package for each Service Pack level. Each roll-up will carry all previously released hot fixes up to one month prior to the release of the roll-up and country specific updates. Each roll-up will be cumulative and will not require the presence of the previous roll-up on the system.
The roll-up package will contain both a cumulative kernel update and a cumulative application update. Although there is no dependency between these two updates, we recommend that you install both of the updates together. The roll-up will be installed on P-layers (i.e. SYP and GLP) and update the SYS layer as well as the GLS layer that is installed on the system.
Links to the RU-4 Knowledge Base articles: