Hi, I am planning 5.5 to 2003 upgrade, and have some questions Thanks in advance for taking you time. ------------------------------------------Current Lineup: 1. Exchange 5.5 to 2003.2. <150 users.3. One domain.4. DC - Windows 2003 Server5. Exchange 5.5 is still a DC - mixed mode.6. Headquarters + 10 remote locations on different subnets.7. Mix of clients: Outlook 98/2003OST, PSTMailbox Names are not the same as NT User Names 8. eXchange POP3 Mail server v.5 (by www.exchangepop3.com) between ISPs mail server and MS Exchange 5.5.9. Blackberry Server v.3.6.4.8 - 7 users 10. 10. Will need OWA.11. Symantec 1660 box -> Cisco -> ISP - routing problems (?) ------------------------------------------Action Plan: Upgrading using "Standard Deployment Method" (MS "Upgrading Exchange Server 5.5 to Exchange Server 2003 Using the Standard Deployment Method"): 1. Run ForestPrep.2. Run DomainPrep.3. Run Active Directory Connector Setup.4. Run Active Directory Connector tools.5. Run Exchange Setup.6. Gradually move users. ------------------------------------------Questions: 1. Is it ok to switch to Exchange 2003 considering everything described in 'Current Lineup' above?2. Will Outlook 98 clients with PST mailboxes be able to connect to Exchange 2003?3. At what point we should (temporarily?) stop mail services on Exchange 5.5? Or 5.5 can continue sending/receiving during upgrade?4. We'll we have to move all the users right away, or can we install the Exchange 2003, and then move users later, in groups of 5-10?5. Will the moved (to E2k3) users still be able to fully utilize Public folders, etc.?6. Will we be able to keep our current user schema: Mailbox = Full real NameNT User Name = Position

If in case you ost becomes unusable then to restore your emails from ost file you can try using Convert OST Software from http://www.convertost.com

Answer: Before you upgrade,suggest you deploy Production in LAB and test eXchange POP3 mail server and Blackberry server Exchange 2003 still support outlook 98 access.Outlook 98 PST file still have 2GB size limit. Exchange 55 can continue send/receive email until you remove exchange 55 or change mail flow to exchange 2003 You must waiting for Exchange 2003 deploy in your ORG and verify everything is ok,then move user mailbox to ex03. Because you AD is Windows 2003 and NT 4 mix mode, during upgrade will not auto convert your exchange 55 distrbution grourp to Windows AD Universalsecuroty group,this will effect you client to access public folder after move to exchange 2003 if befrore use DL to config client permission in exchange 55 PB folder. Yes.