functions. It allows input to be entered in algebraic mode as well as in 4-level classical RPN. The calculator's particular implementation of RPN exhibits an unusual behaviour of the key different from that of the 12C and other classical RPN calculators. The first HP 12c Platinum version (F2231A) did not have parentheses, which often led to awkward key sequences to solve problems in algebraic mode. Since 2005, newer versions (F2232A) of the HP 12c Platinum have parentheses on the blue-shifted functions of the STO and RCL keys. They also support undo and backspace and provide memory for up to 80 CFj registers. The firmware changes increased the ROM size beyond the capabilities of the original processor, so it was replaced by the Generalplus GPLB31A (still with 6502 core), which is also faster. It was manufactured by Kinpo Electronics. In 2006, Hewlett Packard released a limited edition of the 12c Platinum to commemorate the 25th anniversary of the original 12C's introduction. The HP 12c Platinum 25th Anniversary Edition also has the parentheses feature and features the GPLB31A processor as well. The latest revision of the 12c Platinum was introduced in 2007 (F2231AA). As in the later revisions of the 12C, it features two parallel rather than only one CR2032 cells, but it continues to be based on the GPLB31A processor. In 2008, the HP 12c Prestige (F2233A) was released. It features a gold-colored plate like the original 12C, but is otherwise like the fourth HP 12c Platinum model (F2231AA). Bugs and problems By design, the HP-12C rounds up the number of payments to the next integer, which produces meaningless results when calculating fractional periods. Consequently, solving for n returns a value that is mathematically incorrect vis-a-vis the standard annuity formula and different from the value returned by other financial calculators, Excel, etc. Clones The Aurora FN1000 calculator in clamshell design was closely inspired by the HP-12C in 2003. Capitalizing on the limited availability of the HP 12c Platinum 25th Anniversary Edition, Victor Technology released the Victor V12 in 2007 which was a budget priced clone of the HP 12c Platinum edition. It is also available as BrtC FC-12 in Brazil. The 2010 Compucessory CCS28956 aka Compucessory 28956, a clamshell design, is another clone of the HP 12c Platinum, but with added margin calculation functions (COST, SELL, MGN). It is also available as Procalc FN 1200C in Brazil. The Truly SC123 in