Software For BlackBerry® Pearl (TM) 8100 smartphone
BlackBerry Handheld Software v4.5.0.306 (Multilanguage)

Package Version: 4.5.0.306
Consisting of:

• Applications: 4.5.0.182
• Software Platform: 2.7.0.106
• 8100
  • File name: 8100M_PBr4.5.0_rel306_PL2.7.0.106_A4.5.0.182_AT_amp_T.exe
  • File size: 93.13MB
• 8120
  • File name: 8120M_PBr4.5.0_rel306_PL2.7.0.106_A4.5.0.182_AT_amp_T.exe
  • File size: 97.53MB
• 8300
  • File name: 8300M_PBr4.5.0_rel306_PL2.7.0.106_A4.5.0.182_AT_amp_T.exe
  • File size: 89.91MB

Note: The Software Platform and Applications version numbers can be found under Options-About screen on the handheld.

• Download: OS 4.5.0.182 for the BlackBerry Pearl 8100, 8120 or Curve 8300 from AT&T
• How To:
  • Backup And Restore Your BlackBerry
  • Upgrade your BlackBerry Operating System (OS)

Please report any feedback/findings in the comments.

REMEMBER: It is recommended that you make a backup before attempting to upgrade your BlackBerry just in case something goes wrong during the upgrade process. *

Thanks @AtilaUno!