The version of Tcl used in PlanAhead 14.x and Vivado 2012 is 8.5.
To check the Tcl version used in any release, use the report_environment Tcl command in the Tcl console or Tcl shell and then observe the TCL_LIBRARY value.
For example, in the Xilinx tools 14.2/2012.2 release, the report_environment command will include a line similar to the following:
For additional details about the report_environment command and other Tcl commands see:
The TCLdocumentation for a specific release of PlanAhead toolis provided for in the PlanAhead/ Tcl Command User's Guide (UG789). This document is located here:
The TCLdocumentation for a specific release of Vivado is provided for in the PlanAhead/ Tcl Command User's Guide (UG835). This document is located here:
14.2 Release: http://www.xilinx.com/support/documentation/sw_manuals/xilinx2012_2/ug835-vivado-tcl-commands.pdf