0) backup current Miranda IM installation and profile.1) check your database driver. Edit mirandaboot.ini file, replace 
ShowProfileMgr=smart by 
ShowProfileMgr=yes2) start Miranda IM. You will see profile manage. Check 
Driver column. If driver is MMAP — go to 3. If SQLite — read spoiler
SQLite
Go to New profile tab in profile manager and create new profile with MMAP driver.
Miranda start with this blank profile.
Use Import main menu item.
Choose Other profile and select your old SQLite profile .dat
Import all contacts and all messages.
Close Miranda and delete old SQLite profile manually. Profiles are stored in ProfileDir pah (you can see this path in mirandaboot.ini)
Return 
ShowProfileMgr in mirandaboot.ini to it default state.
3) Download 
IM Updater plugin (x32 or x64 according to your Miranda IM). Unpack 
Plugins dir and 
pu_stub.exe into your Miranda IM program folder.
4) Run Miranda IM.  IM Updater will:
- Replace the core files and the appropriate plugins with their NG equivalents.
- Rename old Unicode plugins that have the trailing W in their names.
- Make a backup of any obsolete plugins.
After the this update, you will have Miranda NG 
0.94.9. Updater should notify you that a newer (last) stable version is available. Or you can check for updates manually via the main menu. After the second update, you will have the newest stable version 
0.95.10. This version still cannot log in to ICQ.
5) Backup your new Miranda NG profile and installation again.
6) Now you can just wait 1-2 days until we push new ICQ protocol to stable version. If you want ICQ immediately, you should switch to development version. Go to Options → Services → PluginUpdater and switch from stable channel to development. Updater runs immediately and you get development version 
0.95.11 with working ICQ protocol.
You may experience that some of your contacts disappeared from the list after logging in. Because old Miranda could store a list of contacts locally, and not on the server. In this case, you should run backup Miranda NG with backup profile (from step 5), see which UINs are missing in 0.95.11 and add them into 0.95.11 via standard 
Find/add contacts dialog. After this, close backup Miranda and use 
Import from 0.95.11 main menu. Choose backup profile (step 5) and import only 
All contacts and messages with checked 
check duplicates chеckbox.
If you have any questions about further NG customization feel free to open new topic in 
Support forum 